Annual/Termination Reports:

[06/29/2009] [01/19/2010] [02/17/2011] [01/04/2012] [01/25/2013]

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Objective 1. To identify and characterize new biological agents, naturally suppressive soils, cultural practices, and organic amendments that provide control of diseases caused by soilborne plant pathogens.<br /> <br /> NY: Several isolates of Rhizoctonia solani and Rhizoctonia-like fungi recovered from naturally infected vegetables were found to infect and survive on corn and other grain crops including oat, rye, sudangrass, wheat and buckwheat. Isolates belonging to AG 2-2 that were originally obtained from table beets were the most pathogenic on corn and other grains as well as beans in greenhouse tests.<br /> <br /> NY: The impact of several crop production systems on the severity and damage of root diseases was assessed using a soil bioassay with beans to determine potential root health status. A total of 305 samples from vegetable, sods/pasture, cash grain, fruit, and dairy corn (silage/grain with manure application) were analyzed in the greenhouse. Bean roots grown in soil samples from the vegetable and cash grain production systems had the poorest root health (highest root rot severity ratings), whereas those from the perennial fruit production systems had the lowest root rot severity ratings. The sods and dairy corn systems were in between and exhibited rather low root rot severity ratings.<br /> <br /> NY: A replicated trial comparing the effect of three tillage systems (ridge-till, zone-till, and plow-till) on yield and root rot severity was conducted on a 14-acre long-term soil health site at the Gates Farm, NYSAES near Geneva, NY. The zone-tilled beans had the highest yield, whereas the yield of those grown under the ridge-till and plow-till were equal. Root rot severity ratings of bean grown under the three tillage systems did not differ and was only moderate in severity. <br /> <br /> CA: Our main focus for this objective is the discovery of pathogen- and/or disease-suppressive soils, in particular those that suppress populations of plant pathogenic nematodes. For a number of years we have investigated a field suppressive to the beet cyst nematode, Heterodera schachtii. The most likely causal agents, Dactylella oviparasitica and Fusarium oxysporum were reintroduced in greenhouse and field microplot trials to fumigated, non-suppressive soil and planted to a host crop. After three weeks, the soil was infested with H. schachtii juveniles. After approximately two months, only D. oviparasitica reduced the population densities of H. schachtii to a similar degree as in the original suppressive soil. The apparent lack of efficacy of the F. oxysporum strain raised questions about strain variability. Twenty-six strains of Fusarium spp. were isolated from colonized cysts or parasitized eggs of H. schachtii. They differed substantially in colony appearance and metabolite production on solid culture media. Phylogenic analysis of their rRNA ITS nucleotide sequences revealed considerable genetic variability. Seven representative strains were individually evaluated in greenhouse tests for their potential to parasitize beet cyst nematode eggs and to cause H. schachtii population suppression. Each test strain was introduced into fumigated soil at a propagule density similar to that of F. oxysporum in suppressive soil. The suppressive soil and its fumigated equivalent served as controls. The nine treatments were arranged in a randomized complete block with four replications. A four-week-old Swiss chard seedling was transplanted into each pot that was infested with 5000 second-stage juveniles of H. schachtii. After 1180 degree days in the greenhouse, all Fusarium strains parasitized H. schachtii eggs, but at considerably different levels. While one strain parasitized less than 10% of the eggs, the most aggressive strain was found in approximately 35% of the eggs. This degree of parasitism was not significantly different from the one observed in the suppressive soil. However, in contrast to the originally suppressive soil, in none of the Fusarium-infested soils was the population of H. schachtii significantly reduced after two nematode generations. This supports our hypothesis that Fusarium spp. were not the primary cause of the population suppression.<br /> In another project we collected soil from several California locations that have been known to be inhospitable to various plant parasitic nematodes. These were assayed in greenhouse tests for suppressiveness to root-knot nematodes (Meloidogyne incognita). In one soil and with two different hosts, the population of M. incognita was consistently lower than in the fumigated, re-infested check. Aerated steam or soil fumigation eliminated the suppressive factor/s. Non-treated soil transferred the suppressiveness to fumigated, conducive soil. Fungal rRNA gene analysis of root-knot nematode egg masses collected from a series of greenhouse trials identified 11 fungal phylotypes. The phylotype containing rRNA genes with high sequence identity to Pochonia chlamydosporia exhibited the strongest negative associations.<br /> <br /> MN: We have expanded our collection of antagonistic Streptomyces and Pseudomonas isolates from native prairie soils in the upper Midwestern United States, and from diverse natural habitats around the globe, adding approximately 300 new isolates. These isolates are being characterized with respect to their pathogen inhibitory activity. <br /> <br /> WA: Brassicaceous seed meals (BSMs) were evaluated for the potential to control the biologically complex phenomenon termed apple replant disease. Pathogen control via incorporation of BSMs was previously shown to involve a biological or chemical mechanism, which varied dependent upon the target pathogen and with time. BSM-induced suppression of root infection by Rhizoctonia solani is derived in part through amplification of resident Streptomyces populations. BSMs exhibited small differences in capacity to increase Streptomyces numbers, and the ability to control R. solani (Mazzola et al., 2007a). More recently, it was determined that there was no association between antagonistic potential of individual resident Streptomyces spp. isolates and control of Rhizoctonia root rot, that induction of plant defense responses does have a role in the capacity of certain Streptomyces isolates to elicit disease suppression, that composition of the resulting Streptomyces populations was dramatically altered in a BSM-specific manner, and that certain components of the resulting community while not functioning as apple root pathogens, could amplify R. solani root infection. A BSM that yielded a more uniform Streptomyces community exhibited a reduced capacity to control R. solani.<br /> One of the long-term goals of this research is to develop new and more sustainable strategies to manage soil-borne plant pathogens. To accomplish this, we are endeavoring to understand soils that naturally inhibit plant pests and disease, termed suppressive soils. Key steps in realizing the potential of these soils are to identify the causal organisms and then understand the agronomic and environmental factors that enable them to function. Armed with such knowledge, it should be possible to develop effective and sustainable pest management strategies through the application of the organisms and through agronomic practices that influence their populations. Towards this goal, the first Specific Objective of this research is to elucidate the interactions among the beneficial microorganisms, pathogens and crops that lead to the development and stability of the pathogen suppressiveness. To date, we have identified several fungi involved in suppressing sugarbeet cysts nematodes (Dactylella oviparasitica and Fusarium oxysporum) and root-knot nematodes (Pochonia chlamydosporium and a Tetracladium sp.). Current research is to elucidate the interactions among the beneficial microorganisms, nematode and crops that lead to the development and stability of the suppressiveness. <br /> Another long-term goal of this research is to develop new and more sustainable strategies for managing replant suppression. Replant suppression is a disease or disorder that often occurs when crops are "replanted" in soil that had previously supported the same or similar plant species. It typically leads to reductions in plant growth, crop yields and production duration. As the causal agent(s) remain ill-defined, the second Specific Objective of this research is to identify the microorganisms that cause Prunus replant suppression. Identifying the causal agents will represent a crucial step in the development of new management strategies, as this will facilitate targeted breeding programs and or the selection of targeted biological, chemical or integrated pest management strategies, thereby eliminating the need for soil fumigants such as methyl bromide. To date, we have obtained strong evidence that two stramenopile species (a diatom and Pythium ultimum) are the causal agents of Prunus replant disease in a peach orchard soil. <br /> <br /> OH: We characterized the effects of different farm management strategies on native populations of microbes and plant health. The use of compost for building fertility in transitional organic cropping systems led to improvements in soil fertility and soil structure leading to dramatic increases in yield potential. And, regardless of fertility level, mixed hay cropping provided durable soilborne pathogen suppression. These results suggest that mixed hay can be used as a useful cover crop or mixed-species green manure to provide vegetable growers with naturally disease suppressive soils. <br /> <br /> NM: Seed treatment with biofungicides (Micro108 and Kodiak), and transplant treatment with biofungicides (Mycostop Mix and Actinovate AG) and botanical extracts (garlic extract and Capsicum oleoresins) were tested for effectiveness against Phytophthora blight (Phytophthora capsici) on chile pepper. Seeds treated with a chemical fungicide (Apron XL LS) and seeds not treated (control) were included in the experiments. Although seed treatment did not significantly afford plants with protection against P. capsici after seedlings were transplanted in soil infested with P. capsici, results show that plant protection could be achieved with treatment of transplants with botanical extracts. Pungent Capsicum oleoresins were shown to have the potential to reduce Phytophthora blight on chile pepper.<br /> <br /> OR: We are conducting studies in horticultural nurseries to identify sources of Phytophthora contamination in potting media and soil and developing recommendations for specific cultural practices that will be effective in eliminating those sources of contamination. We are also developing an online course to better educate nursery personnel about Phytophthora diseases in their nurseries.<br /> <br /> CA: We are assessing the significance of insects in the acquisition and dissemination of root-infecting pathogens belonging to the Phyla Oomycota (Pythium and Phytophthora spp). We are searching for chemical substrates which selectively enhance resident populations of fluorescent pseudomonads in amended recycled irrigation water. We are continuing studies on the identification of the soil microbes and other factors that induce germination of ascospores of Monosporascus cannonballus. We are looking at the association of Olpidium bornovanus association with vine decline of melon. <br /> <br /> WA: Novel phenazine producers are predominant in dryland wheat soils.<br /> Phenazine produced by fluorescent pseudomonads was initially hypothesized to be involved in take-all suppression in the late 1970s. This work was mostly done in irrigated plots to favor take-all. Later work with molecular tools in the mid 1990s implicated phloroglucinol producers as being responsible for take-all suppression. However, this work was also done in irrigated fields and in the high rainfall areas of eastern Washington. Recent sampling work at a dryland plot in which we identified possible Rhizoctonia suppression has recovered high numbers of phenazine producing bacteria, both Pseudomonas and Burkholderia. Several important discoveries have been made. High levels of phenazine have been detected from the rhizosphere of wheat and barley growing on this site, using mass spectroscopy. This group of phenazine producers is widespread across the low rainfall dryland region in wheat. Based on sequences of the biosynthesis genes for phenazine and 16s rDNA genes, these strains are unique from previous strains, and are closest to Pseudomonas orientalis. Some of the strains are active against Rhizoctonia in vitro. Irrigation completely shifts the population toward phloroglucinol producers. Phenazine producing strains may be involved in Rhizoctonia suppression and patch disappearance at this site.<br /> <br /> WA: Composition of Rhizoctonia and Pythium spp. in cereal cropping systems is influenced by cropping systems and climatic zones.We are continuing our survey of eastern Washington, using real-time PCR to quantify 10 Pythium spp. and 6 Rhizoctonia groups. We have picked up some broad trends. R. solani AG-8 is found in high populations in low rainfall areas with sandy loam, areas with patch symptoms under direct seeding. In higher rainfall areas of the Palouse, AG-8 is detectable but not quantifiable. R. oryzae is found in annually cropped areas. R. solani AG 2-1 is associated with grain legume rotations. P. ultimum and P. irregulare Group 1 are found in high rainfall areas with grain legume rotations, but not in low rainfall areas with summer fallow. However, P. irregulare group 4 is widely distributed across all zones. We also found that most Pythium species, except P. abappressorium and P. irregulare Group 4, were almost absent from fallow treatments. <br /> <br /> WA: Timing of herbicide sprays can greatly affect greenbridge carryover of inoculum from volunteer to planted crop.A second year of field trials were conducted. All seedling measurements were affected by greenbridge treatments. The longer the greenbridge period with green volunteer/weeds before planting, the lower the crop performance. The longer the period of time the weeds and volunteer are killed before planting, the better the crop performance. The critical threshold period was between 2 and 4 weeks before planting. In other words, if the crop is sprayed out less than 2-4 weeks before planting, the crop suffered. The response seemed to be asymptotic after this 2-4 week threshold- i.e. longer periods free of the greenbridge after this threshold period did not always result in additional improvement to the crop. <br /> <br /> WA: Phialophora isolates are more tolerant to phloroglucinol We hypothesized that Ggt isolates from long-term take-all decline may develop resistance to the antifungal compound phloroglucinol (DAPG), which is responsible for natural suppression. We tested a large collection for in-vitro sensitivity to DAPG and virulence in the greenhouse. Most isolates were sensitive to DAPG, with ED90s ranging from 3 to 11 ppm. There was no correlation between sensitivity to DAPG and virulence. However, we also found a population of weakly pathogenic Phialophora (the asexual state of Ggt) strains that are more tolerant of DAPG (5 times more), which were more predominate in long-term no-till, and may be selected for in long-term take-all decline. <br /> <br /> <br /> Objective 2. To understand how microbial populations and their gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. <br /> <br /> MN: We have developed methods to study the effects of agricultural nitrogen applications (urea) on pathogen-antagonist interactions, and specifically whether urea application reduces biocontrol efficacy. <br /> <br /> AZ: We found previously that quorum sensing (QS) is important in biofilm initiation in Pseudomonas. We have identified additional roles for phenazines in the biology of P. chlororaphis 30-84. We have also characterized the role of the RpeA/RpeB negative two component regulatory system in strains 30-84 and P. aeruginosa PAO1. <br /> <br /> NY: In the Smart lab, we are studying the effect of multiple plant activators on plants in the field to determine if induced systemic resistance (ISR)-inducing biocontrol agents are compatible with other systemic acquired resistance (SAR)-inducing compounds. Additionally, a DNA-based macroarray was developed which can detect over 40 fungal and oomycete pathogens simultaneously. This array is effective on soil and plant tissue samples, and is currently being tested on irrigation water. Finally, the development of detection and identification systems for beneficial soil-inhabiting microbes will, together with the pathogen detection arrays, enable growers to know both the pathogen and beneficial content of their soils.<br /> <br /> WA: Previously, the zoosporicidal activity and control of Pythium root rot of flower bulbs by Pseudomonas fluorescens SS101 was attributed, in part, to the production of the cyclic lipopeptide biosurfactant massetolide A. However, when he capacity of strain SS101 and its surfactant-deficient massA mutant 10.24 to suppress populations and root infection by complex Pythium spp., both strains effectively suppressed resident Pythium populations to an equivalent level and ultimately suppressed Pythium root infection to the same degree on all host plants. Pythium spp. populations indigenous to the two soils employed in these studies were composed primarily of P. irregulare, P. sylvaticum, and P. ultimum var. ultimum. These Pythium spp. either do not or rarely produce zoospores, which could account for the observation that both SS101 and mutant 10.24 were equally effective in disease control. Collectively, the results showed that (i) Pseudomonas fluorescens SS101 is very effective in controlling diverse Pythium populations on<br /> different crops grown in different soils and (ii) production of the cyclic lipopeptide massetolide A does not play a significant role in disease suppression. Other, as yet undefined mechanisms appear to play a significant role in the interaction between P. fluorescens SS101 and soilborne Pythium spp. communities (Mazzola et al., 2007b)<br /> <br /> OH: We determined that DAPG and phlD+ Pseudomonas can alter crop root architecture. Specifically, terminal necrosis and secondary root generation were observed. This phenomonenon occurred at concentrations similar to those reported for in situ measurements of DAPG and the induction of host resistance pathways in some plant species. Such changes appeared to affect both tomato and corn, but the greater affects were observed on the dicot species. Preliminary data also indicate that such changes might also affect nutrient uptake in corn. <br /> <br /> WA: In collaboration with Scot Hulbert, we have been using pyrosquencing (454) to look at total bacterial microbial communities in soil based on 16s ribosomal genes, to see how tillage and crop rotation affect community structures. We have conducted two years of sampling from a long-term site near Manhattan, KS, comparing 4 treatments in a 2 X 2 factorial experiment (two rotations- wheat-wheat or wheat-soybean) and 2 tillage treatments (conventional or no-till). Over two years, we characterized over 15,000 sequences, which were classified into bacterial groups. Acidobacteria was the most predominate group, representing almost 20% of the sequences. Gemmatimonads and Actinomycetales were also common. Other common groups were Burkholdariales, Rhizobiales, and Sphingobacteriales. Surprisingly, groups of Acidobacteria were influenced by the cropping practice. For example, Group 2 was more predominate in no-till, while Group 4 was more numerous in the soybean rotation. This new method is a powerful tool to look at total non-culturable microbial communities, and will be used next year in comparing long-term no-till plots to conventional tilled plots in eastern Washington. <br /> <br /> Objective 3. To develop and implement biological control in agriculture.<br /> <br /> NY: A replicated trial comparing the effect of three tillage systems (ridge-till, zone-till, and plow-till) on yield and root rot severity was conducted on a 14-acre long-term soil health site at the Gates Farm, NYSAES near Geneva, NY. The zone-tilled beans had the highest yield, whereas the yield of those grown under the ridge-till and plow-till were equal. Root rot severity ratings of bean grown under the three tillage systems did not differ and was only moderate in severity. The capacity of Brassicaceae seed meals to provide replant disease control, both in greenhouse and field trials, was found to vary in both a seed meal and apple rootstock-dependent manner. When grown in replant orchard soils amended with BSM in the field, apple rootstocks differed in the capacity to support resident Streptomyces populations, with Geneva series rootstocks typically superior to Malling-series rootstocks in this attribute. These same Geneva rootstocks exhibited a greater growth response in the BSM amended soils, typically to a level equivalent to that attained through soil pasteurization or fumigation. Among those evaluated, Brassica juncea seed meal provided superior control of Pythium spp. and Pratylenchus penetrans, whereas lesion nematode control in response to Brassica napus seed meal was only attained on rootstocks (Geneva series) that maintained an inherently lower P. penetrans populations (Mazzola et al., 2009).<br /> <br /> WA: Evaluation of limestone amendments for control of Fusarium wilt in a spinach seed crop, 2006 Lindsey du Toit, at the WSU research station in Mt. Vernon, has conducted field trials, to investigate whether limestone amendments can suppress Fusarium wilt of spinach, a major seed crop in NW Washington. If a field becomes infected, it cannot be used seed production for at least 10 years. Fields were planted with the male, a susceptible female and a moderately susceptible female line. In 2006, rates from 0 to 4.2 tons/acre were tested, and rates of 0 to 8 tons in 2007. In 2006, there was a significant interaction between rates and plant lines- with the greatest effects seen in the most susceptible lines. In 2007, rates from 2, 4, 6, and 8 tons reduced wilt, with no interaction between rates and plant lines. All treatments increased soil pH by 0.5 to 1 unit by the end of the season. Future research will focus on the microbial basis of this suppression.<br /> <br /> <br /> Objective 4. Provide outreach, education, extension and technology transfer to our clients and stakeholders- growers, biocontrol industry, graduate and undergraduate students, K-12 students and other scientists.<br /> <br /> AZ: P. chlororaphis 30-84 is used as a model genetic system in microbial genetics laboratory course. In spring 2008 there were 88 total students enrolled in 2 sections of the laboratory course. Each pair of students performed transposon mutagenesis of strain 30-84 and screened for unusual phenotypes. The students then isolated genomic DNA and attempted to clone out the mutated region of the chromosome.<br /> <br /> MN: We are training 4 Ph.D. students in our laboratory.<br /> <br /> OH: The PI facilitated an open discussion session at the annual meeting of the American Phytopathological Society on use and adoption of biological controls in organic agriculture and he also presented a workshop on transitioning to organic agriculture presented by the Ohio Ecological Food and Farming Association. Consultation with industry on biopesticide discovery, testing, and product formulation was also conducted. For organic growers, we developed and distributed the first Extension FactSheet that described the utility of commercially-available microbial biopesticides for plant disease control. <br /> <br /> WA: Dr. Lindsey du Toit has an extension appointment, and devotes much of her time to extension talks and training. <br /> <br /> ARS scientists at Pullman, WA lead a science outreach and engagement program, with<br /> participation by USDA, NRCS, Washington State University Cooperative Extension, WSU Plant Pathology Department, and Bellevue Community College, to The Confederated Tribes of the Colville Reservation and the region surrounding Omak, WA. This is one of the most remote, poorest and underserved regions in Washington State. The program entitled "Pumping-Up the Math and Science Pipeline: Grade School to College" has four components: i) development of energy independence on the Colville Reservation through the production of biofuels; ii) hands-on science education in reservation schools by ARS research scientists, WSU faculty and BCC instructors; iii) development of and participation in on-reservation summer science camps; and iv) employing Native American, Latino and rural high school summer science interns in ARS laboratories. Examples of these activities include: 1) field tests of spring and winter canola varieties and biodiesel production on Colville Reservation land; 2) monthly visits to Nespelem Elementary School and Pascal Sherman Indian School on the Colville Reservation to present science modules, October 2007 to May, 2008) sponsorship of and participation in the Second Annual Skwant Life Science Camp at the Pascal Sherman Indian School (Skwant is translated as 'Waterfalls'), June 2007 (two 1-week sessions for 5th-6th and 7th-8th graders and a total of 70 campers); and 4) molecular biology training for 6 summer high school interns (July 2008) in ARS labs at Pullman. This award-winning program is promoting economic development on the Colville Reservation, enhancing science awareness among Native American, Latino and rural youth, and training the next generation of scientists. Native American reservations and rural communities throughout the Pacific Northwest are requesting expansion of this ARS program to their communities.<br /> <br /> Numerous extension talks were given by members of the group, listed under Publications.<br />

Publications

Impact Statements

1. Identification of regulatory networks will allow manipulation of patterns of gene expression to increase pathogen inhibition.
2. Understanding multiple roles of phenazine secondary metabolites in biofilm development will allow improved root colonization and persistence under field conditions.
3. Results obtained during 2008 will be useful in the development of IPM programs for managing diseases caused by soilborne pathogens on vegetables that are sustainable, ecological and compatible with soil health long-term management practices.
4. The identification of the causal agents of nematode population suppression has provided new strains for the development of biocontrol products. Moreover, elucidation of the ecology and mode of action of these organisms will provide important clues for improving the practical application of natural disease and pathogen control.
5. The development of a BSM-based soilborne disease management strategy would also be a significant advancement in the identifying economically effective alternatives to the use pre-plant soil fumigation for control of apple replant disease.
6. These studies are to identify microorganisms involved in Meloidogyne suppressiveness as well as peach replant disease, which should lead to the development of new and more sustainable strategies to manage these pests/diseases.
7. We developed an approach for identifying sources of contamination by Phytophthora species in nurseries and are now targeting those contamination sources by modifying cultural practices.
8. This research is the basis for the Grower Assisted Inspection Program now involving 23 nurseries in Oregon
9. We developed an online course in English and Spanish to better educate nursery personnel about the biology, symptoms and cultural control of Phytophthora so that they will manage these diseases more effectively.
10. The impact of this research is that it provides pepper producers and industry with information on the efficacy of seed treatment with biofungicides and transplant treatment with biofungicides and botanical extracts in control of Phytophthora blight.
11. Multiple species of Pythium and Rhizoctonia can be quantified in soil using PCR technology. This will lead to better diagnostics for wheat.
12. Wheat cropping systems (crop rotation and fallow) affect species of Pythium and Rhizoctonia, both abundance and population density.
13. Wheat cropping systems (crop rotation and tillage) have a profound effect on communities of non-culturable bacteria.
14. Phenazine producers may play a role in Rhizoctonia suppression in the PNW in low rainfall sites, but are completely displaced by phloroglucinol producers under irrigation.
15. Isolates of Phialophora, closely related to the causal agent of take-all, are more tolerant in their sensitivity to phloroglucinol, an antifungal compound involved in biological control.
16. Carryover inoculum of Rhizoctonia from volunteer and weeds can be reduced by proper herbicide sprayout timing before planting.

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Studies of microbial communities in CA, MN, NY, OH, and WA have indicated signficant variations in soil and rhizosphere communities associated with soilborne disease development and plant disease suppression. In CA and OH, such approaches have already led to the discovery of new biocontrol agents. Future research will focus on better characterizing those differences and how community structure is affected by various farm practices, e.g. incorproation of green manures. Several new collaborations have developed in the past year among various group members.<br /> <br /> Discovery research in MN, NE, OH, and WA has led to the discovery of new and useful biocontrol agents. Future work will aim towards a better understanding of the contributions of those microbial agents to plant disease suppression and the development of such strains, and/or their secretion products, into new biopesticides.<br /> <br /> Research by multiple groups on green manures indicated their general utility for enhancing natural biological control activities. Details of which amendments work best will be the focuse of future research by mutlipel groups. <br /> <br /> Practical field trials in CA, MI, NM, NY, and OH indicate the need to extensively field trial biopesticides. Data on Contans was generally positive, and its value for controlling Sclerotinia diseases was shown. While companies will pay for some contract research, information on proper application and efficacy in regional cropping systems is required to serve grower stakeholders most effectively. <br /> <br /> NY researchers have developed an approach to identify sources of Phytophthora contamination in nurseries. This information provides a scientific basis for the development of Best Management Practices that will be effective in eliminating sources of contamination. <br /> <br /> Multiple research groups in this project have found evidence for the multifactorial nature of plant health promotion, further expanding our understandin of biocontrol in the broadest sense. Such evidence, has led to new hypotheses about the nature of plant-microbe interactions and may lead to a shift in the paradigm currently guiding biological control research.<br /> <br /> Multiple members of this committee (NY, OH, WA) have been actively engaged in the development of extension publications, presentations, and workshops that promote the science-based utilization of cropping practices and inputs that reduce soilborne diseases. Such work provides stakeholders with the information and tools they need to increase crop productivity.<br /> <br /> Objective 1 To identify and characterize new biological agents, naturally suppressive soils, cultural practices, and organic amendments that provide control of diseases caused by soilborne plant pathogens.<br /> <br /> CA: Heterodera schachtii suppression. We determined that the population densities of the H. schachtii, two nematode generations after infestation, were dependent on the population densities of Dactylella oviparasitica and H. schachtii at the time of infestation. ITS analysis of our suppressive 9E field soil identified a new strain of D. oviparasitica. <br /> <br /> CA: Characterization of biological basis for peach replant disease. We identified two stramenopile phylotypes that negatively correlated with peach plant weights (Bent et al. 2009b). These organisms were Pythium ultimum and Sellaphora spp. <br /> <br /> MI: Isolation of beneficial bacteria for controlling soilborne diseases.From the suppressive soil, we have isolated 6 Bacillus spp. that have strong antagonistic characteristics against multiple soilborne pathogens, including Phytophthora spp., Sclerotinia sclerotiorum, and Streptomyces spp. including S. scabies.. These isolates have shown to reduce the severity of potato common scab in the greenhouse, which will be repeated next year.<br /> <br /> MI: Characterization of disease suppressive soil against potato common scab.<br /> We have identified a field that has suppressive soil inhibiting potato common scab in Michigan. This disease suppressiveness was verified to be biological by mixing the soil with autoclaved soil at different ratios or treating the soil with various temperatures, with Streptomyces scabies inoculated in the soil before the treatment. The soil profile was studied using terminal restriction fragment length polymorphs (T-RFLP), and conventional dilution plating using different selective media. Primary data have shown that Bacillus spp., and Streptomyces spp. are to be responsible to the disease suppression.<br /> <br /> MI: A new strain (DS3024) of Streptomyces sp. has been isolated. It was confirmed as a pathogen, but genetically different with any known pathogen Streptomyces species that cause potato common scab. It has txtAB genes that are associated with thaxtomin synthesis, which is a key factor of pathogenesis of the pathogen, but lacks of nec1 gene, which is common in most of the other pathogenic Streptomyces. It is possible that the pathogenic gene cluster has migrated into a new species that is naturally non-pathogenic. This has lead us to survey the Michigan potato production area for more population information: whether this strain is widely distributed and any new species exists in the soil. <br /> <br /> NM: Seed treatment with biofungicides for control of Phytophthora blight on chile pepper. A field study was conducted to evaluate the effect of seed treatment with two biofungicides (Micro108 and Kodiak), a chemical fungicide (Apron XL LS), a plant activator (Messenger), and a plant extract (Capsicum oleoresin at 5% aqueous solution) on development of Phytophthora blight (Phytophthora capsici). Seeds not treated (control) were included in the study. There was no significant difference among treatments with respect to weights of marketable pods and incidence of wilted plants. Seed treatment alone was insufficient in providing season-long protection to chile pepper against Phytophthora blight and other soilborne diseases. This result strengthens the conclusion of 2008 research.<br /> <br /> NM: Use of graminaceous green manures for control of Verticillium wilt on chile pepper. A greenhouse study was conducted to evaluate the effect of green manures from field corn, sorghum, sorghum sudangrass, pearl millet, wheat, and oat on Verticillium wilt (Verticillium dahliae) of chile pepper. Severity of Verticillium wilt was most reduced when infested soil was amended with sorghum sudangrass, wheat, or oat green manures. Graminaceous green manures have the potential to reduce Verticillium wilt on chile pepper.<br /> <br /> NY: Detection and identification of plant pathogens. A membrane-based multipathogen detection macroarray has been developed. The array can detect over 40 fungal and oomycete plant pathogens from plant tissue and soil. We are currently optimizing methods to detect pathogens from irrigation water. The array is also being used to identify pathogens in the rhizosphere following various mixed-species green manure treatments. <br /> <br /> NY: Effects of selected grain crops on survival and infectivity of Rhizoctonia in field microplots: We reported last year that a number of isolates of Rhizoctonia and Rhizoctonia-like fungi obtained from naturally infected vegetable crops were capable of infecting corn. A greenhouse test also showed that the most aggressive isolates to corn were also highly aggressive on beans. A field microplot test was initiated in the summer of 2009 to determine the influence of other grain crops (rye grain, sweet corn, wheat and sudangrass) on the survival and infectivity of three isolates of Rhizoctonia (R-39, AG 2-2; R-43, AG 4; and R-62, Binucleate). The crops were planted in microplots established in an experimental field at the vegetable Research Farm. Seeds of snap bean cv.Caprice were planted in the microplots and maintained for 30 days. Results obtained showed that all the isolates in all the treatments were capable of infecting bean.<br /> <br /> NY: Effect of selected cover crops on root rot severity and yield of dry beans: Seven cover crop treatments (rapeseed, canola, grain pearl millet, rye/vetch, buckwheat, sudangrass and a fallow check) were established in 2007 in a section of our experimental bean root rot field at the Vegetable Research Farm of the NYSAES. After two cycles of growing these crops, plots were planted to dry bean cv.CLRK in June 2009 and root rot severity and yield were assessed. At planting time, soil samples were collected from each plot for conducting the bean bioassay in the greenhouse. In the greenhouse bioassay, root rot severity was reduced significantly only on roots of bean growing in soil planted to a cover crop of sudangrass (Table 2). However, no significant reduction was observed on dry bean grown in the field plots nor there was difference in bean yield (Table 2). The latter suggest that two cycles of cover crops incorporated as green manures are not enough to significantly reduce root rot severity caused by a complex of root pathogens that prevail at this site (Rhizoctonia, Fusarium, Pythium and Thielaviopsis). <br /> <br /> NY: Additional beneficial effects of Trichoderma agents. We have demonstrated that biological control is only a subset of the capabilities of Trichoderma strains for use in plant agriculture. They also control physiological and abiotic stresses such as drought, salt and other factors. They also increase nitrogen use efficiency in crops. This is a very large potential benefit since we think we can reduce nitrogen fertilizer by 30% and still improve plant yields. All of these advantages, including plant disease control, are brought about by the ability of the fungi to colonize plant roots, establish chemical communication with the plant and induce systemic reprogramming of plant gene expression.<br /> <br /> OH: Marker-assisted recovery and characterization of novel biocontrol bacteria. We completed our work on identifying some the components of soilborne disease suppression mediated by a mixed hay cropping in a transitional organic cropping system. Using terminal restriction fragments (TRF) statistically associated with the mixed hay-induced suppressiveness as probes, we were able to recover eight isolates representing the M139 and M141 marked populations. Sequence analyses showed the M139-marked strains to be a novel species most closely related to Mitsuaria chitosanitabida. The M141-marked strains were found to represent a species of Burkholderia not previously cultured. Both sets of strains were able to inhibit a broad spectrum of soilborne pathogens in vitro, and they were also able to suppress lesion development in planta. <br /> <br /> WA: A diversity of novel phenazine producers is predominant in dryland wheat soils.<br /> The biogeography of phenazine producing Pseudomonas spp. was investigated in the large dryland wheat growing region of the inland Pacific Northwest. High populations of phenazine producing strains were found in the low precipitation areas, but not the higher precipitation areas. Irrigation in dryland areas completely shifted populations to phloroglucinol producers. High levels of phenazine were detected in the rhizospheres of plants sampled in the field. Strains were characterized based on phzF and 16S genes. The main group of Pseudomonas clustered with P. orientalis, distinct from 2-79, which clustered with another group - P. synxantha, P. gessardii, and P. libanensis. Strains were genotyped with box PCR and phenotyped with Biolog. 31 genotypes were identified, which clustered into four groups. <br /> <br /> WA: Limestone amendments suppress Fusarium wilt in spinach seed crops.<br /> A field trial was set up to evaluate whether annual applications of limestone amendment at 1 or 2 tons/acre can suppress Fusarium wilt adequately and in an economically-viable manner, to enable a 4-5 year rotation between spinach seed crops. Extensive data was collected for each treatment combination on soil and plant nutrient status, spinach biomass, disease development, seed and soil infection levels by Fusarium and Verticillium (another wilt pathogen of spinach), etc. Each season, soil samples will be assayed for changes in chemical and microbial populations over the duration of the trial. Soil microbial analyses will be completed using 454-pyrosequencing. <br /> <br /> Objective 2 To understand how microbial populations and their gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. <br /> <br /> HI: Isolation of new bacterial biocontrol agents: A number of isolates of the bacterial species Stenotrophomonas maltophilia have been shown to act as biocontrol agents, particularly against fungal pathogens. Based on an extensive survey of Xanthomonas/Stenotrophomonas field isolates, we have selected a S. maltophilia accession isolated from cabbage seed for further study and comparative genomics efforts. This strain is being sequenced with the goal of assembling the entire genome and studying it with respect to genetic markers and phenotypes.<br /> <br /> MN: Pathogen suppressive activity was characterized for rhizosphere microbial communities associated with diverse native plant species in communities with varying plant diversity. Plant communities had been established as part of a long-term ecological research project in 1994. For individual plant species, pathogen suppression varied significantly when the plants were grown in low diversity (monoculture or 4-species) vs. high diversity (16- or 32-species) communities. Pathogen suppressive activity was also characterized for diverse plant communities across the landscape, including prairie, savannah, forest, and wetland sites. Finally, induction of pathogen suppressive activity by plant and microbial compounds was characterized for a diverse collection of microbial antagonists; induction tends to be highly specific, and was more likely among isolates from the same community. <br /> <br /> NE: Development of methods to more efficiently study Lysobacter sp. Strains of Lysobacter enzymogenes, a bacterial species with biocontrol activity, have been detected via 16S rDNA sequences in soil in different parts of the world. In this study, DNA-based detection and enrichment culturing methods were developed for Lysobacter spp. and L. enzymogenes, respectively. In the DNA-based method, a region of 16S rDNA conserved among Lysobacter spp. When L4-F and universal bacterial primer 1525R were used to amplify DNA from various bacterial species, a 1,100-bp product was found in Lysobacter spp. exclusively. The enrichment culturing method involved culturing soils for 3 days in a chitin-containing broth amended with antibiotics. A strain of L. enzymogenes added to soils was detected at populations as low as 102 and 104 CFU/g soil by PCR amplication with L4-F and the culturing method, respectively. When both methods were applied twice to assay 56 soil samples collected from various locations in Nebraska, Lysobacter was detected by PCR in 39, over 70%, of the samples, out of which 5 yielded strains of Lysobacter spp. by enrichment culture. Among 16 isolated strains, all were identified to be L. enzyomogenes, with the exception of a strain of L. antibioticus. <br /> <br /> OH: Characterization of a novel beneficial activity of DAPG-praoduicng bacteria. Application of the DAPG-producing strain Wood1R to seed prior to planting was found to ameliorate abiotic stress disorder when the corn grown in soils with a pH < 5.0. Under such conditions, there was no apparent increase in damping-off or visible root rots, indicating that soilborne pathogen suppression was not the primary mechanism leading to the enhanced plant growth. This work is the first to report the ability of a biocontrol strain to reduce an abiotic stress in crop plants, and suggest that additional investigations into the multivariate responses of plant hosts to biocontrol bacteria should be investigated. <br /> <br /> OH: Towards the discovery of a new genes involved in biological control The genome sequences of four bacterial biocontrol strains were obtained. Preliminary analyses reveal novel polyketide and lipopeptide synthases in the two DAPG-producing strains analyzed. In addition, putative insecticidal protein genes were found in Wayn1, indicating that the strain may also have potential for development as the source of new active ingredients for insect as well as disease control. <br /> <br /> OR: Ecology of Phytophthora ramorum: Chlamydospores of P. ramorum typically germinate at low frequency in the lab. We demonstrated that the frequency of chlamydospore germination is increased by passage through the gut of the Pacific banana slug. P. ramorum sporangia and hyphae that pass through banana slugs also remain viable. Under laboratory conditions, banana slugs can transmit ingested Phytophthora ramorum to leaves and tanoak boles. We do not know if slugs transmit P. ramorum in natural conditions.<br /> <br /> WA: Microbial communities in Rhizoctonia patches are different from surrounding soil: 454 pyrosequencing was used to compare bacterial communities inside and outside of Rhizoctonia bare patches, and in disappeared patches. Samples were taken from a continuous wheat rotation, with 4 blocks, from both bulk and rhizosphere soil. The most dominant group observed in ths study was the Actinobacteria, which accounted for about 45% of the sequences. In the rhizosphere, Pseudomonas, Enterobacteria, Sphingomonas, and Burkholdariales were most common. A number of taxa were in significantly higher rhizosphere frequencies inside of the patches, compared to outside of the patches. These included Flavobacterium, Microbacterium, Phyllobacterium, and Enterobacteriaceae. Fewer showed a tendency to high levels in the disappeared patch. These included Burkholdaria, Dyella, Friedmaniella, and Sphingomonas. Other common taxa were in Myxococcales, Verrucomicrobiales, Caulobacteriales, and TM7_genera_incertae_sedis. Surprisingly few Firmicutes were detected. Results will be confirmed with real-time PCR primers designed to these specific groups.<br /> <br /> WA: Mode of action of phloroglucinol is multi-faceted: Phloroglucinol is an antifungal compound produced by Pseudomonas spp., and is involved in the suppression of a number of pathogens on wheat roots, including Gaemannomyces graminis var tritici. However, little is known about the mode of action of this compound. This question was investigated, using a Saccharomyces yeast mutant library. This library has almost 5000 characterized ORFs annotated to function. We did not find any mutants with increased resistance, but a number of mutants were more sensitive. These could be classified into 3 main groups- ergosterol biosynthesis (membrane function), electron transport/oxidative stress, and V-ATPase synthesis and assembly. This suggests that phloroglucinol affects multiple basic cellular processes, and would be difficult to select for resistance in nature.<br /> <br /> Objective 3. To implement sustainable management strategies for soilborne pathogens that are biologically based and compatible with soil health management practices. <br /> <br /> CA: Evaluations of the biocontrol product Contans (Coniothyrium minitans) against lettuce drop caused by Sclerotinia minor in the Salinas Valley. Field experiments were continued to evaluate both the rates of Contans as well as the efficacy of timing and frequency of application to lettuce. In addition, laboratory experiments to evaluate the hypothesis that the most susceptible phase of S. minor is mycelial for attack by C. minitans were expanded to a range of isolates. The two rates of Contans were applied one week prior to, one wk after thinning, and finally before disking under the crop residue. Endura was applied immediately after thinning and at two weeks post-thinning. A single application of Contans at harvest had disease levels intermediate between the other Contans treatments and unsprayed control. While the lower levels of lettuce drop in Contans treatments were correlated with significantly lower levels of sclerotia, the lower levels of lettuce drop despite the presence of higher inoculum in the Endura treatment was attributable to the prevention of infection by S. minor. Tank mixes of Contans and Endura are incompatible. The ideal approach to lowering lettuce drop infections appears to be to employ Contans to lower the number of sclerotia in soil and Endura to prevent infection within a cropping season.<br /> <br /> CA: Assess the efficacy of various biopesticidal amendments to the recirculating nutrient solution for the suppression of root rot caused by zoosporic pathogens (Phytophthora capsici) and elucidation of the mechanism of suppression. With the exception of sodium salicylate, none of the other chemical amendments to the nutrient solution (i.e., Neem, xylene, zinc oxide, Perasan® or Actigard®) provided either consistent or significant control of the disease. All chemical amendments, except Perasan®, enhanced the total and the fluorescent bacterial population in the nutrient solution. However, the selective enhancement of the fluorescent pseudomonad population (which consisted of several biotypes) varied dramatically (0 to 87%) following each consecutive addition of sodium salicylate to the nutrient solution. The fluorescent pseudomonad population may or may not have contributed to the observed sodium salicylate-mediated suppression of the disease.<br /> <br /> MI: Efficacy trials of biopesticides for control of soybean white mold. This is the third year of trials using biological control to reduce the risk of soybean white mold. Contans (Coniothyrium minitans) had consistently showed the best efficacy, reducing Sclerotinia sclerotiorum sclerotia in soil by 95%. Actinovate (Streptomyces lydicus) had very similar efficacy as Contans on controlling the sclerotia. Potassium silicate had a significant reduction of S. sclerotiorum sclerotia and disease incidence, but less effective as the two mentioned biological control agents. These results were similar in two locations (Plant Pathology Farm and Clarksville). <br /> <br /> NY: Effect of tillage systems, cover crops and crop rotation on root rot severity and yield of peas: The long-term soil health site (about 14 acres) was established in 2003 to assess the effect of tillage systems (no-till, strip-till, and conventional tillage), three cover crops (rye grain, hairy vetch, and no cover/fallow) and 2 rotations (one heavy with vegetables, whereas as the other include grain and forage crops and less vegetables). All the treatments were replicated 4 times (4 blocks, 72 plots) and root health, soil health, and yield data have been collected annually. Root rot severity ratings of roots of peas grown in soil of all the plots were rather low and didnt exhibit the effect of the various practices In addition, growth parameter and yield of peas did not vary among the various practices, which could have been the result of the excessive rainfall that prevailed during moths June and July. The work on this site will be continued for the foreseeable future.<br /> <br /> NY: Utilizing green manures to reduce the severity of Phytophthora capsici on tomato.<br /> In 2009, the Smart lab started a project (in collaboration with the McSpadden-Gardener lab) to identify green-manure cover crops that are effective in reducing the incidence of Phytophthora blight on tomato. We have planted four mixed-species cover crops along with two controls (rye alone and bare ground). The crops will be tilled into the soil in spring 2010 prior to planting tomatoes on raised beds. There are two blocks (with 4 replicates of each treatment per block) so that treatments can be tested against two levels of pathogen inoculum (high and low levels of Phytophthora capsici). Plots will be rated for level of disease and yield. <br /> <br /> OR: Systems approach for producing nursery stock free of plant pathogenic Phytophthora species: We completed a 3-year project to develop a new approach for producing nursery stock free of Phytophthora that could also be applied to other pests and pathogens. Four Critical Control Points (CCPs) were identified: infested soil/gravel substrates, irrigation water, re-used pots, and potting media that has been contaminated by field equipment. The most common source of contamination in all tested nurseries was infested soil/gravel substrate in greenhouses and can yards. Healthy container plants set on these substrates readily became contaminated. We consistently recovered Phytophthora from recycled irrigation water and from containers designated for reuse. Our recommendations highlight the need to improve sanitation practices to target these sources of contamination in nurseries.<br /> <br /> OR: Characterization of pathogen diversity in nurseries. A total of 674 Phytophthora isolates was recovered from Oregon nurseries including 15 Phytophthora species and 7 other Phytophthora taxa. The most frequently isolated species from symptomatic plants were P. citricola, P. cinnamomi, and P. syringae. From gravel substrates, soil, and used containers, the predominant species were P. citricola, P. cinnamomi, and P. cryptogea. From irrigation ponds, most isolates were P. gonapodyides or other Phytophthora taxa belonging to ITS Clade 6. P. parsiana and P. inundata, two pathogens not previously reported from Pacific Northwest nurseries, were also detected. P. cinnamomi, the species most frequently isolated from plants, was never recovered from water. Phytophthora species recovered from specific CCPs differed among nurseries, likely a reflection of different production practices and composition of plant cultivars. <br /> <br /> WA: Brassica seed meals can suppress diseases in apple replant. Brassica seed meals can control control populations of Macrophomina phaseolina in the soil. These include Brassica juncea- (oriental mustard), Brassica napus (canola) and Sinapis alba (white mustard). However, this only occurred in natural soil. However, in pasteurized soil, these treatments did not suppress, indicating the requirement for resident soil microbes. Seedmeal also increased apple yield in apple replant problem trials, but only when used with Ridomil, since some seedmeals can stimulate Pythium. In an organic orchard, at the end of the third growing season, seedmeals gave similar growth to Telone C17.<br /> <br /> WA: Development of a soil bioassay for Fusarium wilt of spinach. Spinach seed growers can lose entire crops to Fusarium wilt despite rotations of 8-16 years between spinach seed crops. Research was initiated to develop a quantitative soil bioassay as a risk assessment tool for growers to select appropriate fields for seed crops to minimize losses to Fusarium wilt. The bioassay entails planting in a sample of soil from the field of interest a set of standard spinach inbred lines with different levels of susceptibility to Fusarium wilt, and monitoring the plants for Fusarium wilt using a quantitative rating scale. Based on promising preliminary results for a greenhouse soil bioassay in 2009, spinach seed growers and seed industry personnel have submitted soil samples from ~50 fields in northwestern Washington to test using the bioassay in the winter of 2009-10. The bioassay will be demonstrated to stakeholders in early March so they can potentially utilize the results in selection of fields for 2010 spinach seed crops. Those fields assayed and planted to spinach in 2010 will be monitored for Fusarium wilt. <br /> <br /> WA: Stunting caused by Rhizoctonia spp. in onion and pea crops following cereal cover crops in the semi-arid Columbia Basin. Empirical evidence suggests increasing problems in the semi-arid Columbia Basin of the Pacific Northwest with seedling blight in onion bulb crops and pea crops planted after incorporating cover crops such as wheat and barley. The problem occurs when onion or pea crops are planted in early spring soon after incorporation of a winter cover crop in strips, with the remaining cover crop left standing to protect emerging onion or pea seedlings from wind and sandblasting. Stunted patches range from <1 to >10 m in diameter. The problem does not occur in the absence of significant decomposing residues. <br /> <br /> WA: Pythium spp. associated with damping-off of organic vegetable crops in the semi-arid Columbia Basin of the Pacific Northwest.Growers and production managers of organic vegetable crops in central and western WA (representing production operations ranging from <5 acres to >6,000 certified organic acres) were interviewed to identify primary concerns regarding damping-off of organic vegetable crops. In summary, large-scale organic farms focused on processing vegetable crops experience the most significant losses to damping-off, primarily during early-season plantings. Many have to replant entire fields or seed at higher populations because of damping-off. None of the growers surveyed uses organic seed treatments because of inconsistent or no efficacy under field conditions. However, some indicated they would pay $100-$150)/acre for seed treatments if the treatments consistently controlled damping-off in cold, wet soils. <br /> <br /> Objective 4. Provide outreach, education, extension and technology transfer to our clients and stakeholders- growers, biocontrol industry, graduate and undergraduate students, K-12 students and other scientists<br /> <br /> NY: 2009 Cornell soil health train-the-trainer workshop in collaboration with the Cornell Soil Health program Work Team: This intensive soil health workshop included a mix of classroom training on the emerging concept of soil health, hands-on laboratory experience in assessment protocols, field assessment of soil health measurements, generating the soil health report and its interpretation, and a field trip to local farms to observe and discuss adopted soil health practices. Another workshop has been scheduled for August 15  19, 2010. Additional information on the workshops and the soil health program at Cornell can be found at our website (http://soilhealth.cals.cornell.edu).<br /> <br /> NY: Disease management strategies for Phytophthora capsici In 2009, Smart gave 13 talks to growers, extension educators and industry representatives on strategies to control Phytophthora blight. Additionally, a new web-site is being developed that will provide fact sheets that can be downloaded. This will provide specific information tailored to home gardeners, organic growers or conventional growers. <br /> <br /> NY: Outreach to K-12 students. We have continued our outreach program to third-grade students in the Geneva City School District (Geneva, NY). Part of this outreach includes a summer science camp, where students study different aspects of food production utilizing a garden that they plant at their school. One week of the 5-week program focuses on the importance of healthy soil to producing healthy vegetables.<br /> <br /> NY: Review of different models of biopesticide development and delivery. We are working on several models of production of biocontrol agents, ranging from classical registered pesticide, large national and international to small biovillage level systems. This topic is the subject of a feature article for Plant Disease that has been accepted with revision<br /> <br /> OH: Outreach and assistance to the biopestide industry. A presentation describing the utility of microbial community profiling for the discovery of novel biocontrol agents was presented at the Spring 2009 meeting of the BioPesticide Industry Alliance in Washington, DC. Additionally, contract research related to the reformulation and testing of a novel biopesticide was conducted in Ohio. Critical review and assistance was provided for the redevelopment of the Biopesticide Industry Alliance web site.<br /> <br /> OR: Development of science-based Best Management Practices for nursery growers. Our use of systems approach has been applied to determine sources of contamination in plant production systems. It will provide a basis for considering alternatives to the current system of end-point nursery stock inspections, and will guide in the development of targeted mitigation strategies. A novel and highly successful component of the project was the interaction between scientists and growers that resulted in development of science-based and practical Best Management Practices. <br /> <br /> OR: Online course on Phytophthora for nursery growers. In 2008, we launched a free online course to teach nursery growers about Phytophthora biology, symptoms, and disease management. Both English and Spanish language versions are available at http://ecampus.oregonstate.edu/workforce/phytophthora/ . In 2009, we had excellent feedback from the nursery industry as well as from college horticulture programs that use this in their curriculum. Several improvements to the course were made in 2009. <br /> <br /> WA: Extension outreach to vegetable growers: L. du Toit has a 40% extension appointment, and devotes much of her time to extension presentations and training growers, state department of agriculture personnel, consultants, and seed industry personnel in vegetable disease diagnosis and management. Lindsey presents her vegetable seed pathology research to stakeholders in the Pacific Northwest (ID, OR, WA), as well as to end users of vegetable seed produced in this region (e.g., AZ, CA, MI, Ontario) and international seed industry. She works with undergraduates and annually participaesat Mount Vernon High School to promote awareness of agricultural/science careers among youth in the Skagit Valley. L. du Toit and P. Okubara accommodated a WSU undergraduate intern, K. Reed, in each of their programs in 2009 to work on various molecular lab, greenhouse, and field aspects of spinach Fusarium wilt.<br /> <br /> WA: ARS scientists led a science outreach and engagement program to The Confederated Tribes of the Colville Reservation and the region surrounding Omak, WA. This is one of the <br /> poorest and underserved regions in Washington State. The program entitled "Pumping-Up the Math and Science Pipeline: Grade School to College" has four components: i) development of energy independence on the Colville Reservation through the production of biofuels; ii) hands-on science education in reservation schools by ARS research scientists, WSU faculty and Bellevue Community College instructors; iii) development of and participation in on-reservation summer science camps; and iv) employing Native American, Latino and rural high school summer science interns in ARS laboratories. Native American reservations and rural communities throughout the Pacific Northwest are requesting expansion of this ARS program to their communities.

Publications

Impact Statements

1. The microbial community profiling work that is now becoming a widespread research approach has already led to the generation of new leads for biofungicide development.
2. Data on the competitive fitness of Coniothyrium minitans to control S. minor, and may improve its efficacy for lettuce drop control. As there is only one efficacious fungicide for the control of this pathogen, the project will potentially offer additional options for its management.
3. We demonstrated the efficacy of biological control product Contans can be a good method to manage soybean white mold. This has been considered as an alternative method to disease control by Michigan soybean growers.
4. The impact of this research is that it provides pepper producers and industry with information 1) on the inadequacy of seed treatment alone in providing protection of chile pepper against Phytophthora blight, and 2) on the potential of graminaceous green manures in reducing Verticillium wilt on chile pepper.
5. We showed that increased sanitation is needed in horticultural nurseries to prevent diseases caused by Phytophthora spp. Sources of contamination include used containers, infested gravel beds, contaminated irrigation water, and potting media that have become contaminated by field equipment.
6. Identifying the causal agents of replant disease should facilitate the development of targeted agents to control them and of plants that are resistant to them.
7. Specific cultural practices targeting these sources of contamination were developed and implemented in partnership with nursery growers.
8. The online course continues to be a very effective means of putting research results into practice by the nursery industry.
9. Microbial communities in Rhizoctonia patches differ quantitatively and qualitatively, compared to outside of patches.
10. Phenazine producers may play a role in Rhizoctonia suppression in the PNW in low rainfall sites, but are completely displaced by phloroglucinol producers under irrigation.
11. Phlorogluconol has multiple modes of action, making it unlikely that pathogens will quickly develop resistance in agro-ecosystems.
12. Agricultural limestone amendments suppress Fusarium wilt of spinach in acid soils, and may enable spinach seed growers to reduce rotation intervals from 6-15 years to 5-8 years, thereby increasing the capacity for spinach seed production in the US.
13. Brassica seed meals may suppress pathogens involved in apple replant disease, which has significant application given many fumigants, such as methyl bromide, can no longer be used to control this disease.
14. A quantitative soil bioassay being developed for spinach Fusarium wilt shows strong potential as a risk assessment tool for growers to select appropriate fields for planting spinach seed crops to reduce the risk of losses to Fusarium wilt.
15. Delaying planting of onion bulb crops in early spring for 3-4 weeks after incorporation of cereal cover crops may reduce severity of stunting caused by Rhizoctonia spp.
16. Fungicide seed treatments appear to reduce the size and severity of stunted patches in onion bulb crops in early spring, caused by Rhizoctonia spp. that colonize residues of cereal cover crops incorporated into the soil preceding the onion crops. The results may also be relevant to pea crops following cereal cover crops.
17. The benefits of especially nitrogen use efficiency (NUE) are tremendous. On wheat alone in the USA, we could reduce nitrogen fertilizer use by 1.5 billion pounds (30 lb/acre over 66 million acres) and we believe we can still produce greater yields because of the abilities of our new strains to reduce abiotic stresses such as drought. This will save dramatically on water and air pollution.

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Brief Summary of Minutes

Accomplishments

Accomplishments 2010 W-2147 <br /> <br /> <br /> Objective 1. To identify and characterize new biological agents, naturally suppressive soils, cultural practices, and organic amendments that provide control of diseases caused by soilborne plant pathogens.<br /> <br /> CA. We examined a new peach replant disease soil and identified one stramenopile phylotype that negatively correlated with peach plant weights. This organism was Pythium vexans. <br /> <br /> CA. We examined a putative causal agent (Pythium ultimum) of peach replant disease using pathogenicity tests. Results were variable, as one trial showed lower plant weights with the agent while the other showed high levels of variation within treatments. These experiments are being repeated. <br /> <br /> CA- In previously reported research, we identified key microorganisms that suppress the population of a sugar beet cyst nematode (Heterodera schachtii) in a field site on the UCR Agricultural Operations. A model system was developed with the host/pathogen combination Arabidopsis thaliana and H. schachtii to evaluate the ability of D. oviparasitica to suppress cyst nematode reproduction under gnotobiotic conditions. The fungus reduced the average number of females developing on A. thaliana seedlings by close to 80%. No viable eggs developed in parasitized females. All infected females were eventually killed by the fungus. The fungus was never observed within the root, and consequently, cyst nematodes did not become infected until they broke through the root surface and were exposed to the rhizosphere. <br /> <br /> CA- In another project, a population of M. incognita was found to be suppressed by biological factors. Three genetically different strains of the fungus Pochonia chlamydosporia were isolated from parasitized root-knot nematodes.<br /> <br /> CA- To assess the efficacy of a zoosporic hyperparasitic species of Pythium (i.e., P. periplocum) in the control of two pathogenic species of Pythium (i.e., P. aphanidermatum and P. myriotylum). All three species have inflated sporangia. However, the hyperparasite can be distinguished from the plant pathogenic species base on the presence of spines on the oogonial walls. All three species are ecologically similar in their temperature requirements for vegetative growth and all three species produce zoospores, putting them on equal footing with respect to motility. The working hypothesis is that the hyperparasites, via zoospores, will follow the pathogen into infected root tissue and, via parasitism of the hyphae of the pathogen, inhibit reproduction and growth of the pathogen. Results- Pythium periplocum colonized cucumber roots infected by pathogenic zoosporic Pythium species, but the rapidity of colonization by the hyperparasite was not fast enough to prevent or reduce disease severity caused by the plant pathogenic species. Oospores of both the pathogen and hyperparasite were observed in colonized root tissue. <br /> <br /> CA- To evaluate the efficacy of sodium salicylate in the management of subclinical and clinical zoosporic pathogens of hydroponically-grown lettuce.<br /> Results- Sodium salicylate at 1, 10, 25, 50 and 100 ug /ml in the recirculating nutrient solution did not provide control of root disease caused by either Pythium dissotocum ( a subclinical root-infecting pathogen) or Phytophthora drechsleri ( a clinical root-infecting pathogen) of hydroponically-grown lettuce. Additionally, the chemical, at all concentrations except 1 and 10 ug/ml, were phytotoxic. Other chemical treatments (Revus and Presidio, at 1, 0.5 and 0.1 ug a.i./ml) were efficacious in management of root rot caused by these two pathogens. <br /> <br /> CA- To assess the role of Olpidium bornovanus in vine-decline of melons in the field and evaluate the efficacy of surfactants in control of root rot caused by Olpidium bornovanus. <br /> Field trials were conducted (in collaboration with Dr. Donna Henderson) at the Desert Research and Extension Center in Holtville, Ca. The field plot was naturally infested with both M. cannonballus and Olpidium bornovanus. Chemical treatments (which were applied at periodic intervals over the growing season via the drip irrigation system) included the following: Agral 90 (a non-ionic surfactant), and two fungicides: Cannonball and Quadris. Melons were sown on March 17th and the crop was harvested on June 23rd. Root rot severity ratings indicated that the surfactant treatment was not significantly different that the non-treated control. Root rot severity was significantly lower in the Cannonball and Quadris treatments compared to the control and Quadris was superior to Cannonball. <br /> <br /> CA. To identify the microbe involved in the induction of germination of Monosporascus cannonballus ascospores. Monosporascus cannonballus, a host-specific root-infecting ascomycete, is the causal agent of a destructive disease of melons known as vine-decline. Ascospores, which function as the sole survival propagules and primary inoculum for this soilborne fungus, germinate only in the rhizosphere of melons growing in field soil. However, no ascospore germination occurs in the rhizosphere of melons if the field soil is heated to temperatures greater that 50°C prior to infestation with ascospores. This observation suggests (i) that germination is mediated by one or more heat-sensitive members of the soil microflora and (ii) that melon root exudates alone are not the germination stimulant. Results: Although bacteria or actinomycetes were heretofore suspected as the germination-inducing microbe(s), our recent data demonstrate that the culprit is an obligate, holocarpic, root-infecting zoosporic fungus known as Olpidium bornovanus. Ascospore germination in sterile field soil occurred only in the rhizosphere of melon roots that were colonized by a host-specific melon strain of O. bornovanus. <br /> <br /> MI- Characterization of disease suppressive soil against potato common scab. We have successfully used pyroseqeuencing, bioinformatic and computational methods in a small-scale pilot study with limited samples to study rhizosphere-associated soil microbes from the PCS 'conducive' and 'suppressive' soil. The total operational bacterial taxa from both disease conducive and disease suppressive soil differ both in total numbers and shared number of taxa. The diversity of bacterial Phyla, Classes, Orders, Families and Genera found in the conducive and suppressive soil samples was 20, 49, 87, 173 and 335 respectively. The number of bacterial taxa in disease conducive and suppressive soils was 565, 859, respectively. 26.69% of bacterial taxa are shared by the two types of soils. <br /> <br /> MI- Diversity of pathogens that cause potato common scab. Sequence comparison indicated multiple species from the same tuber, between fields in proximity, and in the same county. Three isolates from tubers collected from Monroe County showed sequence similarity to Streptomyces stelliscabiei, the first confirmed report in MI. However, isolates from other potato fields from the same county could only be identified to Streptomyces spp. One isolate lacked nec1 and one isolate lacked tomA. All isolates in this study were txtAB positive based on PCR analysis.<br /> <br /> OH- Marker-assisted recovery and characterization of novel biocontrol bacteria. We initiated a multifactor screen to quantify the effects of different factors structuring plant-associated bacterial populations. Three collections were developped, each containing over 1000 isolates. Genotyping of these collections using amplified rDNA restriction analysis revealed between 62 and 132 genotypes in each. From these over 400 isolates were selected to determine the degree of fine-level diversity present. Chi-squared analyses of the genotype data revealed that certain factors had a greater impact on the recovery of novel genotypes, and that simple changes in in situ and ex situ sampling protocols could be used to recover different species of bacteria. High through put phenotyping of these strains is underway, but preliminary indications are that over a dozen isolates, some of them belonging to novel species, were obtained with efficacy equal to or greater than an organically-acceptable commercial biopesticide standard.<br /> <br /> OR. Ten horticultural nurseries were investigated for the frequency of Phytophthora contamination in each of three Critical Control Points in the production process: used containers, irrigation water, and gravel underlying container yards. Five of the nurseries were participants in a nursery certification program, the Grower-Assisted Inspection Program (GAIP), sponsored by the Oregon Dept. of Agriculture, and five nurseries were not (non-GAIP). The frequency of contamination was determined by baiting of soil and water samples collected in fall and spring. Overall, there were no significant differences in the frequency of contamination between GAIP and non-GAIP nurseries. The timing of water sampling appears to be very important, with significantly greater recovery of Phytophthora in fall as compared to spring. Used pots and gravel were a source of Phytophthora in several nurseries, and irrigation water was contaminated in most nurseries that did not treat their water, including two of the GAIP nurseries. Several of the nurseries adopted best management practices to curtail their Phytophthora contamination problems as a result of our study. Because of our findings, the Oregon Dept. of Agriculture will require that nurseries participating in GAIP must disinfest recycled irrigation water.<br /> <br /> WA-Cereal cyst nematodes have become established in Eastern Washington, and may significantly reduce yields. Waitea circinata (Rhizoctonia oryzae) has been isolated from most cereal production areas in the U.S., but its pathogenicity is unknown. <br /> <br /> WA-Rhizoctonia solani AG8 appears to be the predominant AG associated with stunting in onion bulb crops following winter cereal cover crops.<br /> <br /> WA-Pythium irregulare Group I, P. ultimum, P. torulosum, P. adhaerens, P. middletonii, P. dissotocum, P. abappresorium and P. violae are amongst the most common Pythium species found in certified organic fields in the irrigated region of the Columbia Basin of central WA.<br /> <br /> <br /> Objective 2 To understand how microbial populations and their gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. <br /> <br /> MS. Our project, "Transcriptomic Dissection of the Interaction Between Oryza sativa and Burkholderia glumae" started in Jan. 2011 and will end in Dec. 2011. We are working to accomplish our objectives.<br /> <br /> OH. Towards the discovery of a new genes involved in biological control. In collaboration with Korean researchers, the genome sequence for Chromobacterium strain C61 was determined. The strain was found to harbor a disproportionate number of chitinase genes as well as a novel NRPS gene. Random and site directed mutagenesis have been used to reduce biocontrol activity of this strain, in order to determine which products might be involved in disease suppression.<br /> <br /> WA-Microbial communities within a Rhizoctonia diseased area in a field are different from the surrounding areas, both qualitatively and quantitatively. These communities may be responsible for long-term suppression of Rhizoctonia disease under no-till conditions. <br /> <br /> Objective 3. To implement sustainable management strategies for soilborne pathogens that are biologically based and compatible with soil health management practices. <br /> <br /> MI. Effect of chestnut extract/tissue in inhibiting soilborne plant pathogens. Extracts from chestnut leaves, shells, and pellicles were all inhibitory to various microorganisms. Bacteria were more sensitive than fungi to the extract. Effective concentration for 50% growth inhibition (EC50) varied, depending on the microorganisms tested. Of the tested microorganisms, Pseudomonas fluorescens was the most sensitive (EC50 = 4.4 ug/uL), and Phytophthora cambivora was one of the least inhibited (EC50 = 185 ug/uL). Extracts of the chestnut type 'Colossal' showed a greater inhibition than those of Chinese. High temperature did not affect the inhibitory effect. Pellicle and shell extracts reduced disease caused by Streptomyces scabies in the greenhouse. The active compounds were identified as tannins and flavanoids. <br /> <br /> MI. Effect of Bacillus sp. BAC03 on Streptomyces scabies. In the greenhouse, Bacillus sp. strain BAC03 significantly reduced scab symptoms in radish. BAC03 also increased the biomass of radish by 40% compared to the non-treated pots, both of which were infested with S. scabies. <br /> <br /> MI. Effect of essential oil in inhibiting Phytophthora capsici. Among the 14 essential oil tested, red thyme, oregano, and palmarosa exhibited high antifungal activity against Phytophthora capsici and Streptomyces scabies with both contact and volatile mode. With P. capsici isolate 12899, the EC50 of red thyme, oregano, and palmarosa is 0.06, 0.08, and 0.04 mg/L by direct contact, and 0.08, 0.08 and 0.04 by using volatiles. None of the oils showed inhibition against Sclerotinia sclerotiorum. Essential oils, red thyme, oregano, and palmarosa had a significant inhibitory effect on sporangium, zoospore and oospore production. These oils also exhibited a potential to inhibit germination of spores.<br /> <br /> NM. A greenhouse study was conducted to determine the effects of transplant and soil treatment with biofungicides on the development of Phytophthora blight on chile pepper. Transplants were immersed in 0.1% suspension of two biofungicides (Actinovate and Mycostop Mix) and water (control) three days prior to transplanting. Soil was drenched with 0.1% Mycostop Mix, 0.1% Actinovate, Ridomil Gold EC (1.16 liter/ha), or water (control). Disease severity level was not significantly affected when transplants were treated with Actinovate and Mycostop Mix. The lowest disease severity was observed when soil was treated with Ridomil Gold EC. An effective soil treatment that reduces soil inoculum potential is essential in the management of P. capsici.<br /> <br /> NY- The replicated 9 cover crops (winter rye grain + hairy vetch, oat, sudex, forage radish, red clover, rapeseed, buckwheat, wheat, and a fallow/control) evaluation trial established in four production fields with different management histories (2 acres each) was continued in 2010 (a total of 108 plots). All plots were sampled for root and soil health assessments in May 2010, over-wintered cover crop incorporated and then all the plots were planted to snap bean cv. 'Caprice'. Bean yield was highest in the field with the highest soil health parameters and the lowest root rot severity ratings. The cover crops also greatly affected root health and yield of beans, but varied among the 4 fields. However, yield of beans was lowest and root rot severity ratings were highest with buckwheat as the cover crop. All the cover crops were re-established in the same plots for another cycle of evaluation.<br /> <br /> NY- In collaboration with the Cornell soil health team, the replicated trial on the combined effects of tillage (No-till, Zone-till, Plow-till), cover crop (Rye grain, Vetch, Fallow), and crop rotation (Vegetables vs. Grain/Forage/Vegetable) on soil and root health parameters was continued at the long-term soil health site at the Gates Farm, Geneva. In May 2010, the 72 plots were sampled for assessing root health and soil health prior to any tillage practices. Pickling cucumber was planted in the vegetable rotation (36 plots) and Sudan grass in the other rotation. In 2010, results of the greenhouse soil bioassay showed that root rot severity was significantly affected by crop rotation, only slightly by tillage systems and no measurable effect was observed among the 3 cover crop treatments. However, results accumulated to date suggest that reduce d tillage systems appear to improve the value of measured soil health indicators the most.<br /> <br /> OR- Commercial greenhouses have relied on chemical fumigants and drenches to control soilborne pathogens between cropping cycles, but increasing restrictions on the use of these materials is forcing growers to explore other ways to manage diseases. Parke investigated non-chemical alternatives to fumigation including removal and replacement of substrate, in situ pasteurization, solarization, and solarization followed by soil incorporation of the biocontrol agents SoilGard and RootShield. Solarization for 6 weeks during the summer was not adequate for killing inoculum of Thielaviopsis basicola, Rhizoctonia solani, or Pythium irregulare buried 4" beneath the soil surface, but solarization did reduce damping-off disease in soil bioassays. SoilGard 12G appeared to give some improvement in root quality and plant health. Additional research is proposed to document the effectiveness of solarization and biocontrol amendments under controlled greenhouse conditions in Oregon.<br /> <br /> WA-Brassica seed meals may suppress pathogens involved in apple replant disease, which is significant given many fumigants (e.g., methyl bromide) can no longer be used. <br /> <br /> WA-Wheat varieties with aluminum tolerance can overcome the low yield problems in acid soils of wheat grown in rotation with bluegrass. <br /> <br /> WA-Limestone amendments can effectively suppress Fusarium wilt in spinach seed crops on acid soils, but the degree of suppression is influenced by susceptibility of the spinach parent lines. A soil bioassay can effectively identify the potential risk of spinach Fusarium wilt.<br /> <br /> WA-Fungicide seed treatments do not appear to manage stunting in onion bulb crops caused by Rhizoctonia, but increasing the duration between incorporating cereal cover crops and planting onion bulb crops appears to reduce the severity of stunting.<br /> <br /> WA-Soil fumigation exacerbates the rate of infestation of soil by Verticillium if an infected spinach seed lot is planted, but effective fungicide seed treatments can significantly reduce the rate of seed transmission.<br /> <br /> <br /> Objective 4. Provide outreach, education, extension and technology transfer to our clients and stakeholders- growers, biocontrol industry, graduate and undergraduate students, K-12 students and other scientists<br /> <br /> All- This group conducts outreach and extension to growers, outlined in the publication section under Extension Publications and Outreach.<br /> <br /> OH-Several presentations were made to organic growers related to the availability and efficacy of biopesticides. These were made to the Ohio Ecological Food and Farming Association's annual conference and posted online as part of both eOrganic and Ohioloine extesnion.<br /> <br /> OR- Parke presented her findings on the systems approach for managing Phytophthora diseases at a workshop for growers, at a nursery field day, in a state-wide nursery association seminar, and in an article published in a nursery trade journal (circulation 8,000). She also gave an invited presentation to fellow scientists at the Kanuga workshop on diseases and pests of ornamentals. The research on solarization and biocontrol was presented at a nursery field day. <br /> <br /> NY-An interactive train-the-trainer workshop on soil health issues was held during August 15 - 19, 2010 in collaboration with the Cornell Soil Health Team. Twenty-four participants from across the country and abroad attended the workshop, which consisted of a mix of classroom and laboratory and field hands-on experience with assessment protocols as well as farm visits. Also, over 25 growers, extension educators, and industry personnel attended a cover crop field day on October 19, 2010 to observed and discuss the establishment of diverse cover crops and their potential impact root and soil health parameters as well as yield parameters of the indexing main crop, snap beans. <br /> <br /> WA- Researchers at USDA-ARS in Pullman have developed outreach programs with elementary and high schools on the Colville Reservations, including monthly classes and a summer camp. They also sponsor summer internships and work with Bellevue Community College.

Publications

Impact Statements

1. Identifying the causal agents of replant disease should facilitate the development of targeted agents to control them and of plants that are resistant to them.
2. Microbial communities in Rhizoctonia patches differ quantitatively and qualitatively, compared to outside of patches.
3. Cereal cyst nematodes have spread to the annual cropping wheat areas of eastern Washington.
4. R. oryzae (Waitea circinata) is the most common Rhizoctonia spp. isolated from soils in the cereal growing areas of the upper Midwest, Midwest, and Plain areas.
5. Wheat varieties with aluminum tolerance may reduce yield losses in acid soils of eastern Washington.
6. Brassica seed meals may suppress pathogens involved in apple replant disease, which has significant application given many fumigants, such as methyl bromide, can no longer be used to control this disease.
7. Soil fumigation can significantly exacerbate the rate of infestation of soil by Verticillium if an infected seed lot is planted, but effective fungicide seed treatments can significantly reduce the rate of seed transmission.
8. Limestone soil amendment can suppress Fusarium wilt in spinach seed crops on acid soils, but the degree of suppression is influenced by susceptibility of the spinach parent lines.
9. A soil bioassay can be used to quantify the potential risk of spinach Fusarium wilt.
10. The development of new Extension materials expanded the visibility of biopesticides among organic growers in Ohio and throughout the United States.
11. Root diseases and soil health are major constraints to vegetable production and profitability in New York State and the NE region. It is known that the use of appropriate cover crop(s) and in the right sequence is one of the few options available for the sustainable management of soil health constraints. Thus, results obtained from these studies will aid growers and other agricultural service providers in selecting the appropriate cover crop(s) and other production practice(s) needed to address the root health and other soil health constraints impacting crop production.
12. The identification of the causal agents of nematode population suppression has provided new strains for the potential development of biocontrol agents. Moreover, elucidation of the mode of action and the ecology of these microorganisms will provide important information for improving the practical application of natural disease and pathogen control.
13. A large number of growers have now heard about the systems approach for managing Phytophthora diseases through workshops, field days, talks and publications, and are implementing best management approaches to minimize their risk of disease.
14. Because of our tests for Phytophthora in nurseries, the Oregon Dept. of Agriculture has decided to change the requirements for growers participating in a nursery certification program (GAIP). Participants will be required to disinfest recycled irrigation water. Previously nurseries were only required to test their water annually, and treat if necessary.
15. Some large commercial growers are now exploring solarization of greenhouses during the summer as an alternative to fumigation.
16. Study of disease suppressive soil will provide useful information in understanding microbial community for soil improvement by using various cultural practices. This has lead to submit NIFA-SCRI research planning grant proposal. Results of chestnut extract may help us to find the active chemical compounds that inhibit plant pathogens, and add additional profit for chestnut growers.
17. The impact of this research is that it provides pepper producers and industry with information on the necessity to implement soil treatments that reduce soil inoculum potential in order to effectively manage Phytophthora blight.

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Report Information

Participants

Abawi, George (gsa1@cornell.edu), Cornell University;

Becker, Ole (ole.becker@ucr.edu), University of California, Riverside;

Borneman, James (james.borneman@ucr.edu), University of California, Riverside;

Eastburn, Darin (eastburn@uiuc.edu), University of Illinois;

Hao, Jianjun (haojianj@msu.edu), Michigan State University;

Harman, Gary (geh3@cornell.edu), Cornell University, Geneva;

Kahn, Michael (kahn@wsu.edu), (Administrative Advisor);

Parke, Jennifer (jennifer.parke@oregonstate.edu), Oregon State University;

Paulitz, Timothy (paulitz@wsu.edu), USDA-ARS, Pullman, WA;

Ploeg, Antoon (antoon.ploeg@ucr.edu), University of California, Riverside;

Stanghellini, Michael (michael.stanghellini@ucr.edu), University of California, Riverside;

Yuen, Gary (gyuen@unlnotes.unl.edu), University of Nebraska

Brief Summary of Minutes

MINUTES

2011 Meeting of the Multistate Project W2147

December 2, 2011

Mission Inn, San Diego Western Room,

Riverside, CA

Jennifer Parke, Acting Chair

Jianjun Hao, Secretary

James Borneman, local arrangements

Members in attendance:

James Borneman, Jennifer Parke, Jianjun Hao, Tim Paulitz, Gary Harman, Gary Yuen, George Abawi, Michael Stanghellini, Michael Kahn (Administrative Advisor), Ole Becker, Antoon Ploeg, Darin Eastburn.

The meeting began with the chairs welcome statement, followed by round table introductions being made informally among the attendees.

Michael Kahn was introduced as the USDA Administrative Advisor. He talked briefly about the multi-state project, followed by some questions.

Gary Yuen was elected to be the secretary for 2012. Riverside (Mission Inn) was decided to be the location of 2012. Meeting date will be determined by email communications.

Borneman described ongoing work related to the characterization of Dactylella-based suppression of the sugar beet cyst nematode.

Paulitz described work on the phz+ strains related to soils suppressive to Rhizoctonia. Disease suppression was analyzed using pyrosequencing.

The group started on state reports. Detailed accomplishments and plans for future work can be found in the full annual report of the committee (which will be sent to all committee members via e-mail at the time of submission).

Parke reported her extension and education work on Phytophthora ramorum in nursery and forestry, including website and best nursery practice method.

Hao discussed on Pythium spp. in carrot from California and Michigan, Bacillus amyloliquefaciens as a biocontrol agent, chestnut extract, and essential oils for disease control.

Following a break, the group discussed on the new proposal due on January 13, 2013. Paulitz went through what has been done on the revision based on the previous version, followed by a short discussion.

Membership in the new proposal renewal was discussed.

Yuen talked about characterization and sequencing of Lysobacter enzymogenes, his teaching and research program.

Abawi discussed on the Cornell Soil Health program and the website, as well as soil management using cover crops.

Harman talked about the mechanisms of Trichoderma spp. on plant growth enhancement.

Stanghellini reported on the relationship between Olpidium bornovanus and Monosporascus cannonballus for disease expression.

Eastburn presented on soybean disease suppression using cover crops.

Ploeg talked about the effect of mustard meal on nematode control.

Becker discussed a patent product for nematode control.

A picture was taken for the group.

In the last section, the group discussed on the proposal writing. All four objectives from current project remain with slight modifications. Each objective was assigned to several members for drafting.

Submitted: Jianjun Hao

Accomplishments

Accomplishments 2011 W-2147<p> <br /> <br /> <br /> <b>Objective 1. To identify and characterize new biological agents, naturally suppressive soils, cultural practices, and organic amendments that provide control of diseases caused by soilborne plant pathogens.</b><p><br /> <br /> CA- A greenhouse bioassay to determine the presence of biological suppressiveness against the beet cyst nematode. In a survey with mustard-greens, two of 48 soils from fields in southern California tested positive for significant suppressiveness against H. schachtii. The data furthermore suggested that various soil textures allow for suppressiveness against H. schachtii. The number of white female nematodes visible through the transparent surface of the test container was correlated with the number of extractable cysts per 100 g soil. Thus, female counts provided good estimates of the final H. schachtii population density. The percentage of parasitized eggs was an unsuitable predictor of soil suppressiveness for this nematode.<p><br /> <br /> CA- A native chytrid induces germination of root pathogen. Olpidium bornovanus was isolated from native desert soils which indicate that Olpidium bornovanus, like Monosporascus cannonballus, are indigenous root-infecting, soil-borne plant pathogenic fungi. Additionally, O. bornovanus was identified as the soil microbe involved in the induction of gerrmination of ascospores of Monosporascus cannonballus.<p> <br /> <br /> CA- Biocontrol of sugar beet cyst nematode. The suppression of a beet cyst nematode population (Heterodera schachtii) in a field site on the UCR Agricultural Operations is primarily due to the nematophagous fungus Dactylella oviparasitica. Parasitism of the eggs does not appear to play a major role in the population suppression of H. schachtii. The main targets are developing (sedentary) 3rd and 4th stage juveniles and females. No viable eggs developed in parasitized females that were eventually destroyed. We determined the relationships between the amounts of the fungus Dactylella oviparasitica and the plant-parasitic nematode Heterodera schachtii. We anticipate that monitoring both the Dactylella oviparasitica and Heterodera schachtii population levels will lead the development of a more effective predictive tool for making sugar beet planting decisions.<p><br /> <br /> IL-Fall cover crops for management of diseases in soybean. A project to evaluate the effect of various fall planted cover crop treatments on diseases in subsequent soybean crops was initiated in the fall of 2010, with soybean crops planted in the spring of 2011. Cover crop treatments include cereal rye, rape, canola, white mustard, and winter fallow. Plots were established at six locations, three on-farm and three on-station in east-central, southern, and western Illinois, with the cooperation of the University of Illinois, Southern Illinois University, and Western Illinois University. At each location cover crops were planted in the fall of 2010, with rye rape and fallow treatments at the on-farm locations, and all five treatments at the on-station locations. Soil samples were collected in the fall of 2010 (to establish baseline values), and again in the spring of 2011, shortly after planting the soybean crop, two to three weeks after incorporation of the cover crop debris. Sub-samples of the soils were taken and used for determining population levels of soybean cyst nematodes (SCN) and for DNA extraction. The DNA extracts are being used to determine population levels of selected soybean pathogens and for ARISA analysis to establish microbial community profiles for each soil sample. The remainder of the soil sample for each plot is being used for greenhouse bioassays to evaluate the disease suppressiveness of the soils to selected soybean pathogens (Fusarium virguliforme and Rhizoctonia solani) for each cover crop treatment.<p> <br /> <br /> MI- Characterization of bacterial strain BAC03 for disease control. Bacillus amyloliquefaciens BAC03 displayed a broad spectrum of antagonistic activity against bacteria, fungi, and oomycetes. In greenhouse assays, BAC03 applied in soil significantly reduced scab severity, promoted the growth in both potato and radish, and reduced S. scabies population. Foliar spray with BAC03 did not significantly affect disease severity and plant growth. BAC03 applied in soil inhibited the emergence of radish seedlings, but did not affect potato emergence from seed tuber. An antimicrobial substance extracted from BAC03 by ammonium sulfate precipitation was identified as an LCI protein using liquid chromatography-mass spectrometry. The liquid culture of BAC03 and extracted substance were stable under a wide range of pH, chemicals, and temperatures. The downside of BAC03 was that it affected the emergence of most tested plants, but not potato seed tuber. Therefore, B. amyloliquefaciens strain BAC03 displayed strong antimicrobial activities, suppression of potato common scab and enhanced plant biomass. LCI protein is an important factor for disease suppression. Strain BAC03 has the potential to be developed and marketed as a commercial biocontrol agent.<p><br /> <br /> MI- Microbial community in response to disease suppressiveness. Our results suggest that this suppressive soil has a makeup of bacterial microbes that is different than an adjacent disease infected field. A total of 1,124 OTUs were detected and 565 OTUs (10% dissimilarity) were identified in disease conducive soil and 859 in disease suppressive soil including 300 shared both between sites. Common phyla based on relative sequence abundance were Acidobacteria, Proteobacteria and Firmicutes. Sequences of Lysobacter were found in significantly higher numbers in the disease suppressive soil, as were sequences of Group 4 and Group 6 Acidobacteria. These bacteria have been proven to suppress Rhizoctonia solani, Streptomyces scabies, and Verticillium longisporum. The relative abundance of sequences identified as the genus Bacillus was significantly higher by an order of magnitude in the disease conducive soil. Fluorescent pseudomonads, Bacillus spp. and non-pathogenic Streptomyces spp. were also associated with the disease suppression. This will help to inform and develop biologically based sustainable disease management practices to reduce pathogen populations in soil and therefore help the potato industry in Michigan by reducing the economic and environmental impacts of PCS disease control.<p><br /> <br /> NM- Plant extracts to control Verticillium dahliae. A growth chamber study was conducted to evaluate the effect of aqueous extracts (4%) from sprouted and non-sprouted oat, wheat, and forage sorghum on chile pepper colonization by Verticillium dahliae. Soil infested with Verticillium dahliae was treated with either each extract or water (control). At five weeks after emergence, isolation frequency of V. dahliae from seedlings of a chile pepper cultivar planted in the treated soil was greatest in control soil and soil treated with extracts from sprouted and un-sprouted sorghum, and was lowest in soil treated with extracts from sprouted and un-sprouted oat and wheat. These results suggest that crop residues from wheat and oat may reduce chile pepper colonization by V. dahliae.<p><br /> <br /> NY- A membrane-based multi-pathogen detection macroarray developed in 2009 continues to be used in new projects including detection of pathogens in irrigation water, and to detect and identify pathogens in the rhizosphere following various mixed-species green manure treatments. We tested 20 irrigation sites across NY in 2010 and 2011, and are currently analyzing the data. In 2010, multiple species of Pythium and Phytophthora were identified, as well as many bacterial species including Clavibacter michiganensis subsp. michiganensis. For the mixed-species green manure treatments, we are collaborating with Brian McSpadden-Gardener (Ohio State University). Because of variable results observed in 2010 and 2011, the experiment will be repeated again in 2012.<p><br /> <br /> NY- Trichoderma helps plants deal with stress. The mechanism of many of these effects has a common element; which is enhancement of redox potential of plants. Stresses, whether biotic or abiotic, frequently result in accumulation of toxic levels of reactive oxygen species (ROS). Photosynthesis also may produce levels of ROS, especially the superoxide anion, that probably decrease photosynthetic efficiency. Plants have mechanisms for redox control, including conversion of the superoxide anion via superoxide dismutase (SOD), and systems to cycle antioxidants from oxidized to reduced forms. This cycling is critical to maintaining healthy redox levels in plants, and under stress, plants do not keep up with the demand. Trichoderma spp. trigger increased expression of genes encoding SOD and the antioxidant cycling enzymes, and so can dramatically reduce effects of stress and improve photosynthetic efficiency.<p><br /> <br /> OH- Characterization of sampling and selection factors on the diversity of bacteria to be screened for biocontrol activities: We developed a multivariate sampling and marker-based selection strategy that significantly increase the diversity of bacteria recovered from plants. In doing so, we quantified the effects of varying sampling intensity, media composition, incubation conditions, plant species, and soil source on the diversity of recovered isolates. Subsequent sequencing and high-throughput phenotypic analyses of a small fraction of the collected isolates revealed that this approach led to the recovery of over a dozen rare and, to date, poorly characterized genera of plant-associated bacteria with significant biopesticide activities. Overall, the sampling and selection approach described led to an approximately 5-fold improvement in efficiency and the recovery of several novel strains of bacteria with significant biopesticide potential.<p><br /> <br /> OH- The basis of general suppression of E. coli O157:H7 assessed using community profiling: All sources of bedding displayed a heat sensitive suppressiveness to the pathogen. Differences in suppressiveness were also noted between different samples at room temperature. All bedding substrates were able to reduce E. coli populations by over 10,000-fold within 7 to 15 dpi regardless of sampling date. Terminal restriction fragment length polymorphism (T-RFLP) analysis was used to identify bacterial populations potentially associated with the noted suppression of E. coli O157:H7 in sand bedding. Eleven of these terminal restriction fragments (TRF) were overrepresented in paired comparisons of suppressive and non-suppressive specimens at multiple sampling points, indicating that they may represent environmentally stable populations of pathogen suppressing bacteria. Cloning and sequencing of these TRF indicated that they represent a diverse subset of bacteria, belonging to the Cytophaga-Flexibacter-Bacteroidetes, Gamma proteobacteria and Firmicutes, only a few of which have been previously identified in livestock manure. Such data indicate that diverse bacteria contribute to the microbial suppression of E. coli and this information may be used to develop new options for mitigating the risk and dispersal of zoonotic bacterial pathogens on dairy farms.<p><br /> <br /> OR- Conducted an international webinar and co-organized a grower workshop on the importance of water for managing waterborne pathogens.<p><br /> <br /> OR- Developed and launched an international website and companion open-source online journal on forest Phytophthora species, many of which are vectored by the nursery plant trade.<p><br /> <br /> OR- Produced a grower manual for how to implement a systems approach for managing pests and disease in horticultural nurseries, and conducted a grower workshop on systems approaches.<p><br /> <br /> WA- Survey of Rhizoctonia species in cereal-producing regions of the US<br /> The first phase of understanding soilborne pathogens is to delineate the extent of the problem and the species composition. We have completed a two-year survey of soils around the U.S., using baiting from soil and identifying the Rhizoctonia groups using sequencing of the ITS region. We have found that R. oryzae (Waitea circinata) and R. solani AG-2-1 are common in most areas. Surprisingly, R. solani AG-8, the cause of bare patch, has not been found outside of the Pacific Northwest.<p><br /> <br /> WA- Survey of cereal cyst nematode (Heterodera avenae) species in Eastern Washington. Despite the prevalence of cereal cyst nematode in NE Oregon, where it was discovered in 1984, little is known about the distribution of this nematode in Washington State. We completed two years of preliminary surveys. We found high populations of this nematode in the Palouse area of eastern Washington. This is a higher precipitation area with annual cropping and a 3-year rotation with a legume. Despite the use of a non-host every 3rd year, this nematode has built up to high populations and may be limiting yields. We also initiated testing of germplasm in sites naturally infested with cereal cyst nematode. We found that lines with the Cre 1 gene showed resistance, as measured by fewer immature cysts on the root system.<p> <br /> <br /> <b>Objective 2 To understand how microbial populations and their gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease.</b><p> <br /> <br /> MS- Transcriptomic dissection of the interaction between Oryza sativa and Burkholderia glumae We are studying the interaction between Oryza sativa and Burkholderia glumae, a soil-borne pathogen and the causative agent of the rice panicle disease. Our objective is to identify differentially expressed genes between a susceptible (CL151) and resistant (CL161) rice genotype, in two developmental stages (seedling and flowering) upon inoculation by B. glumae (strain gr4, kindly provided by Dr. Milton, LSU) and understand the disease process to elucidate the resistant pathway. In this study, we are interested in the gene expression immediately following inoculation. Total RNA was extracted from the tissue samples. Illumina libraries will be constructed from 150-200 bp size range fragments, which will be used for HiSeq2000 sequencing. Genomic DNA was also collected for quantification of the bacterial growth in each sample to be correlated with the gene expression analysis.<p><br /> <br /> NE- Lysobacter enzymogenes as a biocontrol agent of fungal and nematode disease of plants. Strain C3 was demonstrated to produce HSAF (a family of macrocyclic lactams) as one of its important mechanisms of biocontrol. HSAF biosynthetic genes in C3 were partially identified, as was a global regulatory gene clp. Studies in 2011 expanded to include strain OH11 isolated in China. Collaborators in this project sequenced the genome of OH11. By mining the OH11 genome, gene clusters for up to 9 secondary metabolites, including HSAF, were found. The genome sequence revealed all genes in the cluster for HSAF synthesis. In addition, the OH11 sequence revealed that the strain also produces a potent antibiotic (WAP8294A2) with activity against gram-positive bacteria. Although the antibiotic had been reported previously to be produced by a strain of Lysobacter sp., it was not known to be produced by strain C3. Nor has its role in biocontrol been established. Mutant strains deficient in this antibacterial factor have been developed, which will allow definitive testing of biocontrol activity.<p><br /> <br /> OH- Genome sequencing of biocontrol bacteria. We have sequenced and annotated draft genome sequences for Pseudomoans strains Wayn1R, Wood1R, and B001. We have done the same for Chromobacterium sp. C61, Pantoea ananatis B1-9, and Mitsuaria sp. strain H24L5A. These are all now publicly available for comparisons. Preliminary analyses of all indicated a large number of apparently novel operons, the analysis of which will comprise future research efforts to discover novel metabolites and mechanisms of biological control.<p> <br /> <br /> OH-Identification and transcriptional analysis of defense genes induced by root colonization by a bacterial biocontrol agent. Root colonization of Arabidopsis thaliana with Pseudomonas chlororaphis O6 induces systemic tolerance against diverse pathogens, as well as drought and salt stresses. In this study, we demonstrated that 11 genes in the leaves were up-regulated, and 5 genes were down-regulated as the result of three- to five-days root colonization by P. chlororaphis O6. The identified priming genes were involved in cell signaling, transcription, protein synthesis, and degradation. In addition, expression of selected priming genes were induced in P. chlororaphis O6- colonized plants subjected to water withholding. Genes encoding defense proteins in signaling pathways regulated by jasmonic acid and ethylene, such as VSP1 and PDF1.2, were additional genes with enhanced expression in the P. chlororaphis O6-colonized plants. This study indicated that the expression of priming genes, as well as genes involved in jasmonic acid- and ethylene-regulated genes may play an important role in the systemic induction of both abiotic and biotic stress due to root colonization by P. chlororaphis O6.<p> <br /> <br /> WA- Biogeography of phenazine producing Pseudomonas spp. across dryland wheat fallow regions. Over the last 4 years, our group has been describing this unique community that produces significant amounts of phenazine in the roots of dryland wheat, but is displaced by phloroglucinol producers in irrigated wheat or in higher rainfall regions. We have identified 4 main taxonomic clusters by sequencing a number of genes. Two of the clusters are undescribed. One cluster is similar to P. orientalis, and the other to P. lebanesis/synxantha. We looked at the distribution of a collection of over 200 isolates, and tried to correlate it with soil edaphic factors, using canonical correspondence analysis. These included soil texture, organic matter, pH, calcium carbonate, cation exchange capacity, bulk density, and water holding capacity. The correlations were weak, except for a higher association of P. lebanensis with higher sand content.<p> <br /> <br /> WA- Microbial communities in responsible for Rhizoctonia decline. We have identified a site in Ritzville, WA that has gone into Rhizoctonia decline after 12 years of continuous wheat and direct seeding (no-till). Disease reached a peak after 5-6 years and has declined significantly from years 7-10. We are using community analysis techniques and 454 sequencing techniques to identify microbes that may be responsible for this. We found a higher frequency of Actinomycetes such as Kineosporia, Arthrobacter, Friedmanniella, Nocardiodes, Blastococcus and Kribbella in the no-till soil. These genera were also more frequent in the bulk soil than the rhizosphere soil. In the long-term conventional soil, Gemmatimonas and Acidobacter groups 1 and 3 were more frequent. In the rhizosphere of diseased plants in patches, Oxalobactereacea, Sphingobacteria, Acetobacteriaceae, and Xanthomonadaceae were were in higher frequency. In the rhizosphere of plants from healthy areas, Gemmatimonas and Acidobacteria group 3 were in higher frequency. Surprisingly, Pseudomonas and Bacillus made up less than 2% of the total sequences.<p> <br /> <br /> <b>Objective 3. To implement sustainable management strategies for soilborne pathogens that are biologically based and compatible with soil health management practices.</b><p> <br /> <br /> <br /> CA- A biological seed treatment for nematodes. Seed coating with abamectin (Avicta®) provided considerable early season protection against root-knot nematodes in carrot field trials. The active ingredients of the product are metabolites of Streptomyces avermitilis. Preseason cropping with various brassicas and consequent biofumigation by soil incorporation of mowed biomass was not useful under southern California conditions as the cover crops increased root-knot nematode population (M. javanica).<p><br /> <br /> MI- Managing potato common scab using bio-based materials. Essential oils (EOs) from red thyme, oregano, clove bud, citronella java, cinnamon leaf, and bay were all effective for inhibiting S. scabies with Effective concentration fro 50% inhibition (EC50) values between 0.46 to 0.63 ug/ml on average, while EOs from sweet fennel, lavender, palmarosa, peppermint, sage, spearmint, tea tree and rosemary had no impact. Oregano EO reduced the soil population of S. scabies by 10,000 times, while Clove bud EO reduced it by 10 times. Most EOs evaluated were phytotoxic and reduced plant emergence if they were planted or seeded immediately after soil treatment with EOs. In the greenhouse, potato common scab was significantly reduced by BAC03, and horseradish extract. More importantly, BAC03 promoted the growth of potato plants, and induced the plant disease resistance. This effect was strengthened by multiple applications of BAC03 in the soil. Seed treatment with BAC03 protected both potato and radish from disease. The biomass of radish increased as BAC03 applications increased.. BAC03 was able to induce systemic resistance in plants.<p><br /> <br /> MI- Managing soybean white mold using biological control agents. The population of C. minitans was not affected significantly overall by any of the tested chemicals, and mixing period up to 4 hours. Therefore it is safe to mix Contans (C. minitans) in a tank in hours. Coniothyrium minitans was not affected by chemicals such as Eminent, Subdue Maxx, Previcur Flex and Domark, while Trichoderma gamsii and T. asperellum were not affected by Revus, Heritage, and Endura. In the field, both C. minitans and Streptomyces lydicus reduced the sclerotial population of Sclerotinia sclerotiorum and white mold incidence, although they did not fully control the disease. There was no difference between fall and spring treatments. Herbicide Cobra significantly reduced the disease incidence.<p><br /> <br /> NY- Cover crops and soil health. A second year evaluation of the replicated 9 cover crop treatments (winter rye grain + hairy vetch, oat, sudex, forage radish, red clover, rapeseed, buckwheat, wheat, and a fallow/control) was completed in 2011. Again, pod yield of snap beans cv. Caprice was highest in the field with the highest soil health quality (Future-IPM production system) and lowest in the conventionally managed field. In the former field, bean yield was highest in the rye+vetch cover crop plots and lowest in the buckwheat plots. Root rot development was moderate to severe, but varied only slightly among the treatments. All cover crop treatments were re-established in the same plots for final evaluations in 2012. The analysis of the data collected in 2011 and previously is continuing.<p> <br /> <br /> NY- Tillage, rotation, and soil health. In collaboration with the Cornell soil health team, the combined effects of tillage practices (No-till/ridge-till, Zone-till, Plow-till), cover crops (Rye grain, Vetch, Fallow), and crop rotation (Vegetables vs. Grain/Forage/Vegetable) were evaluated by planting all the 72 plots to snap bean cv. Caprice in 2011. Pod yield of bean was highest in the ridge-till and zone-till plots and was lowest in the plow-till plots. Root rot severity on bean roots was moderate and was only lower on roots of plants grown on the ridge-till plots. Again, reduced tillage practices appear to improve measured soil health indicators, but final data analysis is still in progress.<p><br /> <br /> WA- Brassica seed meals can suppress diseases in apple replant. Brassica seed meals are as effective as fumigation in overcoming replant disease, but only when applied the previous fall before planning. These include Brassica juncea- (oriental mustard), Brassica napus (canola) and Sinapis alba (white mustard). In a long-term organic trial in apples, these seed meal treatments reduced populations of Pratylenchus penetrans more than fumigation with Telone C-17. At 17 months, these treatments resulted in apple seedling growth comparable to the fumigant, significantly greater than the non-treated control.<p><br /> <br /> WA- Testing of organic seed treatments for pea and corn. In replicated field trials at two locations in 2011, organic seed treatments were tested for control of Pythium damping-off. At Mt. Vernon, no treatment was effective on peas, except for Apron. For sweet corn, primed seed and Natural II significantly increased emergence. At irrigated trials at Boardman, OR, under high disease pressure, seed priming and Nordox increased emergence and yield of peas. At Soap Lake, with less disease pressure, treatments had no effect on emergence, but Nordox and Mycostop increased plant height of peas.<p> <br /> <br /> <b>Objective 4. Provide outreach, education, extension and technology transfer to our clients and stakeholders- growers, biocontrol industry, graduate and undergraduate students, K-12 students and other scientists.</b><p><br /> <br /> All- This group conducts outreach and extension to growers, outlined in the publication section under Extension Publications and Outreach.<br /> http://phytophthora.pppmb.cals.cornell.edu/ <p><br /> <br /> NE- Gary Yuen at University of Nebraska-Lincoln co-teaches the only distance-delivered biological control course in the nation. Biological Control of Pests, delivered via the internet, reaches 20 to 25 graduate students every other spring semester. Yuen also teaches Introductory Plant Pathology to 40 to 50 undergraduate students every fall semester. In this course, biological control is presented as a critical component of integrated disease management. In both courses, examples of research and implementation from W2147 are used to illustrate these facets.<p> <br /> <br /> NY- Disease management strategies for Phytophthora capsici. In 2011, Smart gave 8 talks to growers, extension educators and industry representatives on strategies to control Phytophthora blight. Additionally, a new web-site has been developed that will provide fact sheets and information that can be downloaded. The site can be found at _______________________ <p><br /> <br /> NY- Major outreach activities dealing with root health, soil health and/or root diseases in 2011. A cover crop field day was held at the Vegetable Research Farm near Geneva, NY on October 19, 2010. Twenty-five growers and extension educators participated in a discussion focused on the project objectives, available results, and each was provided with plot maps for personal viewing of the 4 study fields. Abawi on behalf of collaborators made presentations at the Soil Health Session at the Empire State Fruit and Vegetable Expo in Syracuse, NY on January 27, 2011 (80 growers and other agricultural service providers in attendance), at the 2011 NYS Dry Bean meeting held in Stafford, NY on March 3, 2011 (70 in attendance), at the Delaware Fruit and Vegetable Conference held in Harrington, Delaware on January 19, 2011 (100 in attendance), and 7 additional presentations at formal and informal meetings. Furthermore, new participatory training workshops on the identification, assessment and management of soilborne plant pathogens in vegetable production systems in the NE region were initiated in 2011 in collaboration with Beth Gugino (Penn. State University) and Jim LaMondia (Connecticut Agricultural Experiment Station) with financial support from the NE-SARE program. The first workshop has been scheduled for December 7, 2011 in Windsor, CT,; whereas 6 additional workshops will be presented during the next two years. The target audiences for these workshops are growers, extension educators, crop consultants, IPM practioners, and other agricultural service providers.<p><br /> <br /> NY- Outreach to K-12 students. We have continued our outreach program to third-grade students in the Geneva City School District (Geneva, NY). Part of this outreach includes a summer science camp, where students study different aspects of food production utilizing a garden that they plant at their school. One week of the 5-week program focuses on the importance of healthy soil to producing healthy vegetables.<p><br /> <br /> NY- Undergraduate research experience. In 2009, the Plant Pathology and Plant-Microbe Biology Department on the Geneva Campus of Cornell University established a summer scholars program to increase the involvement of undergraduate researchers in applied agricultural sciences. Each summer, several students are involved with projects that are part of the W2147 multi-state project. During the summer of 2011, three students in the Smart lab were working on Phytophthora capsici detection in 1) irrigation water and 2) tomato plant rhizosphere samples and the third student worked on the population biology and evolution of the pathogen. Additionally, an undergraduate student in the Abawi lab worked on nematode problems in vegetables.<p><br /> <br /> WA- Researchers at USDA-ARS in Pullman have developed outreach programs with elementary and high schools on the Colville Reservations, including monthly classes and a summer camp. They also sponsor summer internships and work with Bellevue Community College.<p><br /> <br /> WA. L. du Toit has a 40% extension appointment, and devotes much of her time to extension presentations and training growers, state department of agriculture personnel, consultants, and seed industry personnel in vegetable disease diagnosis and management. Lindsey presents her vegetable seed pathology research to stakeholders in the Pacific Northwest (ID, OR, WA), as well as to end users of vegetable seed produced in this region (e.g., AZ, CA, MI, Ontario) and international seed industry players in the U.S., Canada, Denmark, England, France, the Netherlands, New Zealand, and South Africa).<br /> <br />

Publications

Refereed Publications and Abstracts<br /> <br /> Abawi, G. S., C. H. Petzoldt, B. K. Gugino, and J. A. LaMondia. 2011. Prioritizing cover crops for improving root-health and yield of vegetables in the Northeast. Phytopathology 101: S1 (Abstr.).<br /> <br /> Alcala, A. C., Paulitz, T. C., Porter, L. D., and du Toit, L. J. 2011. Profile of Pythium spp. in certified organic fields for vegetable production in central Washington. APS Annual Meeting, Honolulu, Hawaii, 6-10 August 2011. Phytopathology 101:S4. http://www.apsnet.org/meetings/Documents/2011_Meeting_Abstracts/a11ma21.htm <br /> Balaji, V. and Smart, C.D. 2011. Over-expression of snaking-2 and extension-like protein genes restricts pathogen invasiveness and enhances tolerance to Clavibacter michiganensis subsp. michiganensis in transgenic tomato (Solanum lycopersicum). Transgenic Research (in press).<br /> <br /> Balaji, V., Sessa, G., and Smart, C.D. 2011. Silencing of host basal defense response-related gene expression increases susceptibility of Nicotiana benthamiana to Clavibacter michiganensis subsp. michiganensis. Phytopathology 101:349-357.<br /> <br /> Becker, J.O., and J. Smith Becker 2010. A screening and optimization test for nematicidal seed coatings. J. Nematology 42:233.<br /> <br /> Becker, J.O., J. Nunez, and A. Ploeg 2010. Abating root-knot nematode damage in fresh carrot production. J. Nematology 42:232-233. <br /> <br /> Bennypaul, H.S., Mutti, J., Kumar, N., Rustgi, S., Okubara, P.A., Gill, K.S. 2011. Virus-induced gene silencing (VIGS) of genes expressed in root, leaf and meiotic tissues of wheat. Functional Integrative Genomics. DOI: 10.1007/s10142-011-0245-0. <br /> <br /> Chekali, S., Gargouri, S., Paulitz, T.C., Nicol, J., Rezgui, M. 2011. Effects of Fusarium culmorum and water stress on durum wheat in Tunisia. Crop Protection 30: 718-725.<br /> <br /> Cho SM, Park JY, Han SH, Anderson AJ, Yang KY, Gardener BBM, and Kim YC. 2011. Identification and transcriptional analysis of priming genes in Arabidopsis thaliana induced by root colonization with Pseudomonas chlororaphis O6. The Plant Pathology Journal, 23:272-279.<br /> <br /> <br /> D'Aes, J., Khuong, H.G., De Maeyer, K., Pannecoucque, J., Forrez, I., Ongena,<br /> M., Dietrich, L.E., Thomashow, L.S., Mavrodi, D.V., Mavrodi, O.V., Hofte, M.<br /> 2011. Biological control of Rhizoctonia root rot on bean by phenazine- and cyclic lipopeptide-producing Pseudomonas CMR12a. Phytopathology. 101:996-1004.<br /> <br /> De Luna, L.Z., Kennedy, A.C., Hansen, J.C., Paulitz, T.C., Gallagher, R.S., Fuerst, E.P. 2011. Mycobiota on wild oat (Avena fatua L.) seed and their caryopsis decay potential. Plant Health Progress. doi:10.1094/PHP-2011-0210-01-RS.<br /> doi:10.1128/AAC.05370-11 <br /> <br /> du Toit, L.J. 2011. Effects of soil fumigation and seed treatments on seed transmission of Verticillium in spinach. Page 41, International Spinach Conference, 3-4 October 2011, Amsterdam, The Netherlands (poster). http://spinach.uark.edu/Spinach%20Conference%20Program%20Final%20092611.pdf <br /> <br /> du Toit, L.J. 2011. Selecting a spinach seed health assay for Verticillium: Results of an ISHI ring test. Page 28, International Spinach Conference, 3-4 October 2011, Amsterdam, The Netherlands (paper). http://spinach.uark.edu/Spinach%20Conference%20Program%20Final%20092611.pdf <br /> <br /> du Toit, L.J., and Correll, J.C. 2011. Assessing the significance of seedborne Verticillium in spinach. Page 18, Programme and Abstracts, 47th Congress of the Southern African Society for Plant Pathology, 23-26 January 2011, Kruger National Park, South Africa.<br /> <br /> Dung, J., du Toit, L.J., and Johnson, D.J. 2011. Verticillium wilt of skullcap and potential for pathogen dissemination via seeds and stems. Plant Disease 95: 1147-1152.<br /> <br /> Dung, J.K., du Toit, L.J., Gatch, E.W., and Johnson, D.A. 2011. Cross-pathogenicity of Verticillium dahliae isolates from skullcap and peppermint. Phytopathology 101:S247. 2010 APS Pacific Division/Canadian Phytopathological (CPS) annual meeting, Vancouver, BC. http://www.apsnet.org/members/divisions/pac/meetings/Pages/2010MeetingAbstracts.aspx <br /> <br /> Dunn, A.R., Milgroom, M.G., Meitz, J.C., McLeod, A., Fry, W.E., McGrath, M.T., Dillard, H.R., and Smart, C.D. 2010. Population structure and resistance to mefenoxam of Phytophthora capsici in New York State. Plant Disease 94:1461-1468.<br /> <br /> Gatch, E.W., and du Toit, L.J. 2011. Managing Fusarium wilt in spinach seed crops using limestone and a soil bioassay. Phytopathology 101:S248. 2010 APS Pacific Division/CPS annual meeting, Vancouver, BC. http://www.apsnet.org/members/divisions/pac/meetings/Pages/2010MeetingAbstracts.aspx <br /> <br /> Grünwald, N. K., Martin, F. N., Larsen, M., Sullivan, C., Press, C. M., Coffey, M. D., Hansen, E. M., and Parke, J. L. 2011. Phytophthora-ID.org: A sequence based Phytophthora identification tool. Plant Dis. 95:337-342.<br /> <br /> Handiseni, M., Brown, J., Zemetra, R., and Mazzola, M. Herbicidal activity of Brassicaceae seed meal amended soils on emergence and growth of wild oat (Avena fatua), Italian rye grass (Lolium multiflorum), redroot pigweed (Amaranthus retroflex) and prickly lettuce (Lactuca serriola). Weed Technol. 25:127-134. 2011<br /> <br /> Hao, J. J., Liu, H., Gonzalez, I. R. D., Lu, X. H., and Fulbright, D. 2011. Antimicrobial activities of chestnut extracts for potential use managing soilborne plant pathogens. Plant Disease. (In press).<br /> <br /> Hao, J. J., Meng, Q., Rosenzweig, N., Lu, X., and Liu, H. 2010. Managing potato common scab by enhancing soil health. Great Lakes Fruit, Vegetable and Farm Market EXPO. Link: http://www.glexpo.com/abstracts.php. <br /> <br /> Harman, G. E. 2011. Multifunctional fungal plant symbionts: new tools to enhance plant growth and productivity. New Phytol. 189:647-649.<br /> <br /> Harman, G. E. 2011. Trichodermanot just for biocontrol anymore. Phytoparasitica Guest Editorial. 39: 103-108.<br /> <br /> Harman, G. E., Obregón, M. A., Samuels, G. J. and Lorito, M. 2010. Changing models for commercialization and implementation of biocontrol in the developing and developed world. Plant Dis. (feature article). 94:928-939.<br /> <br /> Harper, K., Smart, C.D. and Davis, R.M. 2011. Development of a DNA-based macroarray for the detection and identification of Amanita species. Journal of Forensic Science 56: 1003-1009.<br /> <br /> Hooks, C., Wang, K.H., Ploeg, A.T., McSorley, R. 2010. Using marigold (Tagetes spp.) as a cover crop to protect crops from plant-parasitic nematodes. Applied Soil Ecology. Vol. 46: p.307-320. <br /> <br /> Kandel, S., Elling, A., Smiley, R.W., Garland-Campbell, K, Nicol, J.M. and Paulitz, T.C. 2011. A survey of root lesion nematode (Pratylenchus spp.) in the dryland wheat production areas of eastern Washington. Presented at the 50th Annual meeting of the Society of Nematology, Corvallis, OR, July, 2011. <br /> <br /> Kelley, E., and Hao, J. 2010. Effect essential oils on inhibition of Phytophthora capsici. Phytopathology 100: S60 (abstr.).<br /> <br /> Kim, Y.C., Leveau, J., McSpadden Gardener, B.B. Pierson, E.A., Pierson, L.S. III, and C.-M. Ryu. 2011. The multifactorial basis for plant health promotion by plant-associated bacteria. Appl Environ. Microbiol. 77:1548-1555<br /> <br /> Lamprecht, S. C., Tewoldemedhin, Y. T., Calitz, F. J., and Mazzola, M. Evaluation of strategies for the control of canola and lupin seedling diseases caused by Rhizoctonia anastomosis groups. European Journal Plant Pathology 130: 427-439. 2011.<br /> <br /> Lamprecht, S. C., Tewoldemedhin, Y. T., Hardy, M., Calitz, F. J., and Mazzola, M. Effect of cropping system on composition of the Rhizoctonia populations recovered from canola and lupin in a winter rainfall region of South Africa. European Journal of Plant Pathology 131:305-316. 2011.<br /> <br /> Li, Q., Mavrodi, D.V., Thomashow, L.S., Roessle, M., Blankenfeldt, W. 2011.<br /> Ligand binding induces an ammonia channel in 2-amino-2-desoxyisochorismate (ADIC) synthase PHZE. Journal of Biological Chemistry. 286:18213-18221.<br /> <br /> López-Pérez, J.A., Roubtsova, T., de Cara-Garcia, M., Ploeg, A.T. 2010. The potential of five winter-grown crops to reduce root-knot nematode damage and increase yield of tomato. Journal of Nematology. Vol. 42: p.120-127.<br /> Lorito, M., Woo, S. L., Harman, G. E. and Monte, E. 2010. Translational research on Trichoderma: from omics to the field. Annu. Rev. Phytopathol. 48: 395-417.<br /> <br /> Lou, L., G. Qian, Y. Xie, J. Hang, H. Chen, K. Zaleta-Rivera, Y. Li, Y. Shen, P. H. Dussault, F. Liu, and L. Du. 2011. Biosynthesis of HSAF, a tetramic acid-containing macrolactam from Lysobacter enzymogenes. J. Am. Chem. Soc.133:643-645.<br /> <br /> Lu, X. H., Davis, R. M., and Hao, J. J. 2011. Comparative study of Pythium species causing carrot cavity spot in California and Michigan. Phytopathology 101: S110 (abstr.).<br /> <br /> Lu, X. H., Hausbeck, M. K., Liu, X. L., and Hao, J. J. 2011. Risk assessment of Phytophthora capsici resistant to fluopicolide. Phytopathology 101: S110. (abstr.).<br /> <br /> Lu, X. H., Hausbeck, M. K., Liu, X. L., and Hao, J. J. 2011. Wild type sensitivity and mutation analysis for resistance risk to fluopicolide in Phytophthora capsici. Plant Disease 95: 1535-1541. <br /> <br /> Lu, X. H., Livingston, S., Nunez, J. J., Davis, R. M., Hao, J. J. 2011. Pythium species associated with carrot cavity spot and their fungicide sensitivity in California and Michigan. Plant Disease. (In press).<br /> <br /> Mastouri, F., T. Bjorkman, and G.E. Harman. 2010. Seed treatments with Trichoderma harzianum alleviate biotic, abiotic and physiological stresses in germinating seeds and seedlings. Phytopathology 100:1213-1221.<br /> <br /> Mastouri, F., T. Bjorkman, and G.E. Harman. 2012. Trichoderma harzianum strain T22 enhances antioxidant defense of tomato seedlings and resistance to water deficit. Molec. Plant Microbe Interact. accepted with revision<br /> <br /> Mavrodi, D.V., Joe, A., Mavrodi, O., Hassan, K.A., Weller, D.M., Paulsen,<br /> I.T., Loper, J.E., Alfano, J.R., Thomashow, L.S. 2011. Structural and functional analysis of the Type III secretion system from Pseudomonas fluorescens Q8r1-96. Journal of Bacteriology. 193:177-189.<br /> <br /> Mazzola, M. Advances in Brassica seed meal formulation for apple replant disease control. Pages 6.1-6.4 in, Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. MBAO, Fresno, CA. 2011. <br /> <br /> Mazzola, M. Potential of biofumigation for soilborne pest control in strawberry. Pages 47.1-48.2 in, Proceedings Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions. MBAO, Fresno, CA. 2011.<br /> <br /> Meng, Q. Liu, H., and Hao, J. 2011. An inhibitory effect of a novel Bacillus sp. strain against potato common scab. Phytopathology 101:S119. (abstr.).<br /> <br /> Meng, Q. Yin, J. F., Rosenzweig, N., Douches, D., and Hao, J. J. 2011. Biological characteristics of suppressive soil to potato common scab in Michigan. Plant Disease. (Accepted)<br /> <br /> Meng, Q., Adesemoye, A. O., Kirk, W. W., Hao, J. 2011. Genetic and morphologic diversity of Streptomyces species that cause potato common scab in Michigan. Phytopathology 101: S244. (abstr.).<br /> <br /> Meng, Q., Cui, X., Bi, Y., Wang, Q., Liu, X., and Hao, J. 2011. Biological and genetic characterization of Phytophthora capsici mutants resistant to flumorph. Plant Pathology 60:957-966. <br /> <br /> Moebius-Clune, B.N., O.J. Idowu, R.R. Schindelbeck, H.M. van Es, D.W. Wolfe, G.S. Abawi, Gugino, B.K., 2011. Developing Standard Protocols for Soil Quality Monitoring and Assessment. In: Bationo, A.; Waswa, B.; Okeyo, J.M.; Maina, F.; Kihara, J.M. (Eds.) Innovations as Key to the Green Revolution in Africa: Exploring the Scientific Facts. Springer. ISBN: 978-90-481-2541-8.<br /> <br /> Ochiai, N., Dragila, M. I., and Parke, J. L. 2011. Pattern swimming of Phytophthora citricola zoospores: an example of microbial bioconvection. Fungal Biology 115:228-235.<br /> <br /> Okubara, P.A., Jones, S.S. 2011. Seedling tolerance to Rhizoctonia and Pythium in wheat chromosome group 4 addition lines from Thinopyrum spp. Canadian Journal of Plant Pathology 33: 415-422.<br /> <br /> Parke, J. L. and Rizzo, D. M. 2011. Phytophthora ramorum. Forest Phytophthoras 1(4). DOI:<br /> <br /> Paulitz, T.C. 2011. Disease management. In: Hatfield, J.L. and Sauer, T.J., editors. Soil management: building a stable base for agriculture. Madison, WI: American Society of Agronomy and Soil Science Society of America. p. 265-274.<br /> <br /> Paulitz, T.C. and Steffenson, B.J. 2011. Biotic stress in barley: disease problems and solutions. In: Ullrich, S.E., editor. Barley: improvement, production and uses. Ames, IA: Wiley-Blackwell. <br /> <br /> Ploeg, A., J. Nunez, and J.O. Becker. 2010. Cover cropping and seed coating to mitigate root-knot nematode damage in carrot. Communications in Agricultural and Applied Biological Sciences (Comm Agr Appl Biol Sci) 75: 476.<br /> <br /> Poole, G., Smiley, R. Paulitz, T.C., and Garland-Campbell, K. 2011. Identifying quantitative trait loci (QTL) for resistance to Fusarium crown rot (Fusarium pseudograminearum) in two spring wheat populations. Phytopathology 101: S144. (abstr.).<br /> <br /> Rosenzweig, N., and Hao, J. 2011. Characterizing microbial communities of potato common scab suppressive soil using pyrosequencing. Phytopathology 101: S156. (abstr.).<br /> <br /> Rosenzweig, N., Tiedje, J. M., Meng, Q., Quensen III, J. F., and Hao, J. J. 2011. Soil microbial communities associated with potato common scab suppressive soil. Plant Disease. (Accepted)<br /> Sanogo, S., Liess, L., and Richman, R. 2011. Mycelial growth and sporangial production of Phytophthora capsici as affected by extracts from pecan tissues. Phytopathology 101:S159.<br /> <br /> Schroeder, K.L,. Shetty, K.K. and Paulitz, T.C. 2011. Survey of Rhizoctonia spp. from wheat soils in the U.S. and determination of pathogenicity on wheat and barley. Phytopathology 101: S161. (abstr.).<br /> <br /> Shoresh, G. E. and Harman, G. E. 2010. Differential expression of maize chitinases in the presence or absence of Trichoderma harzianum strain T22 and indications of a novel exo- endo-heterodimeric chitinase activity. BMC Plant Biology 10:136. Published on line http://www.biomedcentral.com/1471-2229/10/136.<br /> <br /> Shoresh, M., Harman, G. E. and Mastouri, F. 2010. Induced systemic resistance and plant responses to fungal biocontrol agents. Annu. Rev. Phytopathology 48: 21-43.<br /> <br /> Spies, C. F. J., Mazzola, M., and McLeod, A. Characterization and detection of Pythium and Phytophthora species associated with grapevines in South Africa. European Journal Plant Pathology 131:103-119. 2011.<br /> <br /> Spies, C. F. J., Mazzola, M., Botha, W. J., van der Rijst, M., Mostert, L., and McLeod, A. Oogonial biometry and phylogenetic analyses of the Pythium vexans species group from woody agricultural hosts in South Africa reveal distinct groups within this taxon. Fungal Biology115:157-168. 2011.<br /> <br /> Spies, C.F.J., Mazzola, M., Botha, W. J., Langenhoven, S., Mostert, L., and McLeod, A. Molecular analysis of Pythium irregulare isolates from grapevines in South Africa suggest a single variable species.. Fungal Biology 115:1210-1224. 2011.<br /> <br /> Stanghellini, M.E. and Misaghi, I.J. 2011. Olpidium bornovanus-mediated germination of ascospores of Monosporascus cannonballus: a host-specific rhizosphere interaction. Phytopathology 101:794-796.<br /> <br /> Tewoldemedhin, Y. T., Mazzola, M., Botha, W. J., Mostert, L., and McLeod, A. Cylindrocarpon species associated with apple tree roots in South Africa and their quantification using real-time PCR. European Journal Plant Pathology 129:637-651. 2011.<br /> <br /> Tewoldemedhin, Y. T., Mazzola, M., Botha, W. J., Spies, C. F., and McLeod, A. Characterization of fungi (Fusarium and Rhizoctonia) and oomycetes (Phytophthora and Pythium) associated with apple orchards in South Africa. European Journal Plant Pathology 130:215-229. 2011.<br /> <br /> Tewoldemedhin, Y. T., Mazzola, M., Labuschagne, I. and McLeod, A. Towards understanding the etiology of apple replant disease in South Africa using a multiphasic approach. Soil Biology and Biochemistry. 43:1917-1927. 2011.<br /> <br /> Westphal, A. Williams, M.L. Baysal-Gurel, F., LeJeune, J.T. and B.B. McSpadden Gardener. 2011. General suppression of Escherichia coli O157:H7 indicated in sand-based dairy livestock bedding. Appl. Environ. Microbiol. 77:2113-2121.<br /> <br /> Yan, G.P., Smiley, R.W., Okubara, P.A. 2011. Detection and quantification of Pratylenchus thornei in DNA extracted from soil using real-time PCR. Phytopathology 101.DOI: 10.1094/PHYTO-03-11-0093. <br /> <br /> Yin, C., Jones, K.L., Peterson, D.E., Garrett, K.A., Hulbert, S.H., Paulitz, T.C. 2010. Members of soil bacterial communities sensitive to tillage and crop rotation. Soil Biology and Biochemistry. 42: 2111-2118.<br /> <br /> Zhang, W, Li, Y, Qian, G., Wang, Y., Chen, H., Li, Y., Liu, F., Shen,Y., and Du, L. 2011. Identification and characterization of the anti-MRSA WAP-8294A2 biosynthetic gene cluster from Lysobacter enzymogenes OH11. Antimicrob. Agents Chemother.<br /> <br /> Zeng, W., Kirk, W., Wang, D., and Hao, J. J. 2011. Field management of Sclerotinia stem rot of soybean using biological control agents. Biological Control. DOI: 10.1016/j.biocontrol.2011.09.012<br /> <br /> Zeng, W., Kirk, W., Wang, D., and Hao, J. J. 2011. Use of Coniothyrium minitans and other microorganisms for reducing Sclerotinia sclerotiorum. Biological Control. DOI: 10.1016/j.biocontrol.2011.10.009.<br /> <br /> <br /> <br /> Extension Publications<br /> <br /> Abawi, G. S., C. Petzoldt, and K. Moktan. 2011. Evaluation of cover crops for improving root health and yield of vegetables. The Empire State Fruit & Vegetable Expo, Syracuse, NY. Proceedings, 4 page summary.<br /> <br /> Abawi, G. S., J. W. Ludwig, and K. Moktan. 2011. Pea root rot and results of variety evaluations. The Empire State Fruit & Vegetable Expo, Syracuse, NY. Proceedings, 4 page summary.<br /> <br /> Abawi, G. S., T. Porch, and J. D. Kelly. 2011. Field and greenhouse evaluation of bean germplasm to root rot and other diseases in New York, 2010. Bean Improvement Cooperative 54: 142 - 143.<br /> <br /> Alcala, A.C., Derie, M.L., Holmes, B., Gatch, E.W., Porter, L.D., Coffman, G., and du Toit, L.J. 201_. Evaluation of organic seed and drench treatments for damping-off in pea and sweet corn in Mount Vernon, WA, 2011. Plant Disease Management Reports 6: submitted Dec. 2011.<br /> <br /> Alcala, A.C., Derie, M.L., Holmes, B., Gatch, E.W., Porter, L.D., Coffman, G., and du Toit, L.J. 201_. Evaluation of organic seed and drench treatments for damping-off in organic pea crops in the semi-arid Columbia Basin, Oregon and Washington, 2011. Plant Disease Management Reports 6: submitted Dec. 2011.<br /> <br /> du Toit, L.J., Derie, M.L., Gatch, E.W., Alcala, A.C., Reed, K., and Holmes, B.J. 2011. Effect of agricultural limestone amendment on Fusarium wilt in a radish seed crop, 2010. Plant Disease Management Reports 5:ST001.<br /> <br /> du Toit, L.J., Derie, M.L., Gatch, E.W., Brissey, L.M., and Holmes, B. 2011. Effect of agricultural limestone amendments on Fusarium and Verticillium wilts in a spinach seed crop, 2008. Plant Disease Management Reports 5:V117.<br /> <br /> Dunn, A.R., Reiners, S. and Smart, C.D. 2011. Cornell Pepper Trials: Yield and Phytophthora Blight Tolerance. Hand out given at an organic pest control meeting and also at the vegetable breeders field day (August, 2011)<br /> <br /> Dunn, A.R., Smart, C.D., Mazourek, M.M. and Lange, H.W. 2011. Update on Phytophthora Resistant Variety Trials. Proceedings of the 2011 Fruit and Vegetable Expo, Syracuse, NY.<br /> <br /> Fisher, P., Meador, D., Parke, J., Wick, R., and Argo, W. 2011. Biological water quality. Greenhouse Management (Oct. 2011 issue) http://www.greenhousemanagementonline.com/gm1011-biological-water-quality-irrigation.aspx<br /> <br /> Gatch, E.W., Derie, M.L., Brissey, L.M., Holmes, B.J., and du Toit, L.J. 2011. Effect of agricultural limestone amendments and nitrogen source on Fusarium wilt in a spinach seed crop, 2009. Plant Disease Management Reports 5:V118.<br /> <br /> Griesbach, J.A., Parke, J. L., Chastagner, G.C., Grunwald, N.J., Aguirre, J. 2011. Safe procurement and production manual: a systems approach for the production of healthy nursery stock. 95 pp. Oregon Association of Nurseries, Wilsonville, OR. http://oan.org/associations/4440/files/pdf/SafeProduction.pdf <br /> <br /> Jones, L.A., Worobo, R.W. and Smart, C.D. 2011 Preliminary Results of Irrigation Water Sampling. Proceedings of the 2011 Fruit and Vegetable Expo, Syracuse, NY.<br /> <br /> Kikkert, R. G., G. S. Abawi, and A. G. Tayler. 2011. Seedling establishment. Legume ipmPIPI Diagnostic Series, http://legume.ipmpipe.org<br /> <br /> Koening, R., Paulitz, T.C., Schroeder, K.L., Carter, A., Pumphrey, M., Huggins, D. and Campbell, K. 2011. Soil acidity and aluminum toxicity in the Palouse region of the Pacific Northwest. Washington State University Extension Publication.<br /> <br /> Lange, H.W. and Smart, C.D. 2011. Efficacy of fungicides for suppression of powdery mildew in acorn squash, 2010. Plant Dis. Mgt 5:V083 DOI:10.1094/PDMR05 <br /> <br /> Lange, H.W. and Smart, C.D. 2011. Evaluation of bactericides for the management of black rot on cabbage, 2010. Plant Dis. Mgt 5:V084 DOI:10.1094/PDMR05<br /> <br /> Miles, E.J., Rangarajan, A. Smart C.D., and Reiners, S. 2010. Cover Crops for Use in Reducing Phytophthora Blight Damage to Bell Pepper (Capsicum annuum). Hortscience 45:S226. <br /> <br /> Parke, J. 2011. A new approach to pests: research into systems approaches is yielding new tools for healthy plant production. Digger 55(8):155-160.<br /> <br /> Parke, J. L. and Lewis, C. 2011. Protecting container-grown plants. Digger 55(2):41-45. http://www.oan.org/associations/4440/files/digger/Digger_FEB_2011_41-45.pdf<br /> <br /> Seaman, A.J., Lange, H.W. and Smart, C.D. 2011. Efficacy of OMRI-Approved Pest Control Products. Handout for our organic pest control meeting. August 2011.<br /> <br /> Smart, C.D. 2011. Tomato Diseases: What do I Have? Proceedings of the 2011 Fruit and Vegetable Expo, Syracuse, NY.<br /> <br /> Smart, C.D. and Dillard, H.R. 2011. Phytophthora Blight: A New Disease of Snap Beans in NY. Proceedings of the 2011 Fruit and Vegetable Expo, Syracuse, NY.<br /> <br /> Smart, C.D., Dunn, A.R., Jones, L.A. and Lange, H.W. 2011. Management Strategies for Phytophthora Blight. Proceedings of the Mid-Atlantic Fruit and Vegetable Convention (p. 81-82).<br /> <br /> Smart, C.D., Dunn, A.R., Jones, L.A. and Lange, H.W. 2011. Prevention is Key: The best way to control Phytophthora blight is to stop the pathogen from showing up on your farm in the first place. American Vegetable Grower, June 2011 p. 10<br /> <br /> Smart, C.D., Herman, M.A.B., Jones, L.A., and Lange, H.W. 2011. Managing bacterial speck and bacterial speck-like diseases on fresh market tomatoes in New York. Proceedings of the 26th annual Tomato Disease Workshop. October, 2011.<br /> <br /> Wohleb, C.H., and du Toit, L.J. 2011. Bacterial diseases of phytosanitary significance for bean crops in Washington State. Washington State University Extension Fact Sheet FS038E, Pullman, WA.<br /> <br /> <br /> Extension and Outreach Presentations<br /> <br /> Becker, O. Sugar beet Research Meeting, Brawley/Holtville, CA, May 5, 2011. "Sugar beet cyst nematode in Southern California: new options for IPM" (invited presentation)<br /> <br /> Becker, O. 22nd Annual Fall Desert Crops Workshop, El Centro, CA, November 29, 2011. "New Developments in Management of Plant Parasitic Nematodes." (invited presentation)<br /> <br /> Becker, O. 50th Society of Nematologists Annual Meeting, Corvallis, OR, July 16-21, 2011. "Investigations into the relatedness of the nematophagous fungi Dactylella oviparasitica and ARF-L." (poster presentation)<br /> <br /> Becker, O. CA Nematology Workgroup Meeting, UC Davis March 22, 2011. "Biorational and biological control of plant parasitic nematodes."<br /> <br /> Becker, O. Joint Meeting of the 57th Annual Conference on Soilborne Plant Pathogens & 43rd Annual California Nematology Workshop, UC Davis, March 21-23, 2011. "Brachypodium: a new model system for plant parasitic nematodes." <br /> <br /> Becker, O. Port of San Diego-UCCE IPM meeting, Chula Vista, CA, May 19, 2011. "Do soil amendments have activity against plant parasitic nematodes?" (invited presentation)<br /> <br /> Becker, O. UCR Turf and Landscape Research Field day 2011, Riverside, CA, September 15, 2011. "A new root-knot nematode in Bentgrass." (invited presentation)<br /> <br /> du Toit, L.J. 2011. Damping-off in carrot. Invited presentation, 35th Internat. Carrot Conf., 30 November  2 December 2011, Johannesburg, South Africa. (invited presentation)<br /> <br /> du Toit, L.J. 2011. Fusarium and Verticillium in relation to spinach seed. Invited presentation at Rijk Zwaan Seed Co. headquarters, 5 October 2011, Delft, Holland. (invited presentation)<br /> <br /> du Toit, L.J. 2011. Management of seedborne diseases. Pacific Northwest Vegetable Association Annual Conference & Trade Show, 16-17 November 2011, Kennewick, WA. http://www.pnva.org/ <br /> <br /> du Toit, L.J. 2011. Onion diseases of sporadic occurrence in the Columbia Basin. Pacific Northwest Vegetable Association Annual Conference & Trade Show, 16-17 November 2011, Kennewick, WA. http://www.pnva.org/ <br /> <br /> du Toit, L.J. 2011. Research on efficacy of organic seed treatments for fungal pathogens: Spinach as a case study. Invited presentation at American Seed Trade Association Organic Seed Workshop, Phytosanitary Measures for Organic or Untreated Seed Sold to Mexico, 20 October 2011, Merida, Mexico. (invited presentation)<br /> <br /> du Toit, L.J. 2011. Rhizoctonia in onion bulb crops: Evaluation of field management practices. Pacific Northwest Vegetable Association Annual Conference & Trade Show, 16-17 November 2011, Kennewick, WA. http://www.pnva.org/ <br /> <br /> du Toit, L.J. 2011. Selecting a spinach seed health assay for Verticillium: Results of an ISHI ring test. International Spinach Conference, 3-4 October 2011, Amsterdam, The Netherlands (paper). (invited presentation)<br /> <br /> du Toit, L.J. 2011. Through the looking glass: Perspectives from a sabbatical in South Africa. Seminar presented to WSU Dept. of Plant Pathology, 26 October 2011, Pullman, WA.<br /> Owen, J., Parke, J. and Fisher, P., Workshop Co-organizers: Water Management for Floriculture and Nursery Crops, Wilsonville and Aurora, OR. Feb. 2-3, 2011. Sponsored by Oregon State University and the Water Education Alliance for Horticulture, University of Florida. 50 participants. Workshop Co-organized<br /> <br /> Parke, J. 2011. A systems approach for managing diseases in nurseries. Oktoberpest Workshop, N. Willamette Research and Extension Center, Oct. 17, 2011. 40 attendees.<br /> <br /> Parke, J. Biology of Waterborne Pathogens. Water Management for Floriculture and Nursery Crops, Wilsonville and Aurora, OR, Feb. 2-3, 2011. 50 attendees.<br /> <br /> Parke, J. Testing Water for Phytophthora. Water Management for Floriculture and Nursery Crops, Wilsonville and Aurora, OR, Feb. 2-3, 2011. 50 attendees.<br /> <br /> Parke, J. L. 2011. A systems approach for managing Phytophthora diseases in nurseries: the importance of water. Water Education Alliance for Horticulture Webinar, Dec. 13, 2011 archived at: www.watereducationalliance.org/video.asp . 51 attendees (international audience). A webinar.<br /> <br /> Parke, J. L. 2011. Forest Phytophthoras of the World www.ForestPhytophthoras.org A new website.<br /> <br /> Paulitz, T.C. 2011. Nematodes: Symptoms and Management. Presented to the Asotin County Extension Grower Workshop, Clarkeston, WA, Dec. 17, 2011.<br /> <br /> Paulitz, T.C. 2011. Root Disease Research at USDA-ARS, Pullman-Whats New? Spokane Farm Forum, Feb. 2011. (invited presentation)<br /> <br /> Paulitz, T.C. 2011. Soilborne Pathogens in Wheat- Fusarium, Rhizoctonia, and Cereal Cyst Nematode. Nez Perce County Grower Workshop, Lewiston, ID, Oct. 18, 2011. <br /> <br /> Paulitz, T.C. and Schroeder, K. 2011. invited seminar Rhizoctonia root rot of cereals: a complex picture at Global Forum on Root Health, West Palm Beach, FL, Feb. 21-24, 2011. (invited presentation)<br /> <br /> Paulitz, T.C. and Schroeder, K.L. Cook Agronomy Farm Field Day, Pullman, WA, June 23, 2011. <br /> <br /> Paulitz, T.C. and Schroeder, K.L. Crop Disease Clinic, Spillman Farm, Pullman, WA, July 6, 2011. <br /> <br /> Paulitz, T.C. Conservation agriculture workshop at CIMMYT, El Batan, Mexico, June 13-18, 2011. Laying the ground for sustainable and productive cropping systems. Gave 6 lectures and training sessions. (invited presentation)<br /> <br /> Schroeder, K.L. and Paulitz, T.C. Gave invited seminar on Rhizoctonia to Syngenta Seedcare meeting, Spokane, WA July 12-14. (invited presentation)<br /> <br /> Schroeder, K.L. Fairfield Field Day, Fairfield and Rockford, WA, June 21, 2011. <br /> <br />

Impact Statements

1. Grower manuals, webinars and websites have been developed to train ornamental nursery personnel to manage Phytophthora diseases
2. Pepper producers and industry are provided with information on the necessity to implement soil treatments that reduce soil inoculum potential and pepper colonization in order to effectively manage Verticillium and Phytophthora blight.
3. A survey of field soil from various sites in Southern California indicated that the occurrence of sugarbeet cyst nematode suppressive fields is rare.
4. Biofumigation with brassica cover crops against M. javanica appears to be not useful under southern California conditions.
5. Seed coatings with natural metabolites of actinomycetes provided significant protection against early season attack by root-knot nematodes in carrot field trials.
6. Microbial communities in Rhizoctonia patches differ quantitatively and qualitatively, compared to outside of patches.
7. Cereal cyst nematodes have spread to the annual cropping wheat areas of eastern Washington.
8. R. oryzae (Waitea circinata) and R. solani AG 2-1 are the most common Rhizoctonia spp. isolated from soils in the cereal growing areas of the upper Midwest, Midwest, and Plain areas.
9. Wheat varieties with aluminum tolerance may reduce yield losses in acid soils of eastern Washington.
10. Brassica seed meals may suppress pathogens involved in apple replant disease, which has significant application given many fumigants, such as methyl bromide, can no longer be used to control this disease.
11. Discovery of biosynthetic genes and controlling mechanisms for antagonism factors in this project may lead to the development of more field-effective biocontrol agents. In addition to providing a new tool for disease management, use of such agents is compatible with other management practices and might result in reduced chemical fungicide inputs.

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Report Information

Participants

Members in attendance:

;

Abawi, George, (gsa1@cornell.edu) - Cornell University;
Becker, Ole, (obecker@ucr.edu) - University of California - Riverside;
Borneman, James, (james.borneman@ucr.edu) - University of California - Riverside;
Eastburn, Darin (eastburn@illinois.edu) - University of Illinois;
Everts, Kathryne, (keverts@umd.edu) - University of Maryland;
Hao, Jianjun, (haojianj@msu.edu) - Michigan State University;
Kahn, Michael (AA), (kahn@wsu.edu) - Washington State University;
Parke, Jennifer (jennifer.parke@oregonstate.edu) - Oregon State University;
Pierson, Elizabeth (eapierson@tamu.edu) - Texas Agrilife Research;
Ploeg, Antoon, (antoon.ploeg@ucr.edu) - University of California - Riverside;
Stanghellini, Michael (michael.stanghellini@ucr.edu) - University of California - Riverside;
Yuen, Gary, (gyuen@unl.edu) - University of Nebraska

;

Guests:

;
Fumiaki Funahashi - Oregon State University;
M. Hamadi - University of California - Riverside

Brief Summary of Minutes

Minutes

2012 Meeting of the Multistate Project W2147

December 7, 2012

Mission Inn, San Gabriel Room

Riverside, CA

James Borneman, Acting Chair and local arrangements

Gary Yuen, Secretary

Members in attendance:

George Abawi (NY), Ole Becker (CA), James Borneman (CA), Darin Eastburn (IL), Kathryne Everts (MD), Jianjun Hao (MI), Michael Kahn (USDA program director), Jennifer Parke (OR), Elizabeth Pierson (TX), Antoon Ploeg (CA), Michael Stanghellini (CA), Gary Yuen (NE)

Guests: Fumiaki Funahashi (OSU), M. Hamadi (UCR)

The meeting began at 8:30 AM with the acting chairs welcome and introduction of attendees.

Michael Kahn explained the funding structure of multistate projects and provided update on the federal Farm Bill.

Ole Becker was elected to be secretary for 2013. Gary Yuen will be the 2013 chair. Mission Inn, Riverside, CA was chosen as the location for the 2013 meeting, tentatively scheduled for Friday December 6.

Tim Paulitz (USDA-ARS) was recognized for his contributions to W2147 and proceeding projects, particularly his extraordinary leadership in preparing the current and past project renewal proposals.

Reports of progress began with D. Eastburn's update on cover cropping research in IL.

M. Stanghellini (CA) reported on the taxonomic affiliation of a new desert fungus (Desbotaca) with the unique ability to establish mycorrhizal association with crucifer plants.

Gary Yuen described recent research in NE on the biocontrol bacterium Lysobacter enzymogenes and reported on educational activities relative to biological control.

Ole Becker summarized CA field experiments on biological products for nematode control directed to carrot producers.

Oregons report was presented by F. Funahashi, who described experiments evaluating solarization and biological control agents for control of Phytophthora spp. in nurseries.

G. Abawi summarized research and outreach efforts in NY relative to soilborne diseases of green bean.

J. Borneman discussed recent findings in CA on Dactylella oviparasitica, a fungal parasite of nematodes.

A. Ploeg reported on a unique interaction of the root knot nematode with pepper in the Cochella Valley, CA.

K. Everts outlined on-going research in MD on the use of green manure and cover crops and biological control agents to control pathogens such as Fusarium oyxsporum f. sp. nivium and Sclerotinia sclerotiorum.

J. Hao provided an overview of his work in MI, including research on Bacillus amyloliquifaciens BAC03, a biocontrol agent being developed into a commercial product.

An overview of research in TX on the role of phenazines and the regulation of phenazine production by pseudomonads was given by E. Pierson. She also highlighted the development of LAMP PCR as a detection method for the pathogen of zebra chip disease.

M. Kahn shared elements of his research on Sinorhizobium meliloti.

Members worked in small groups to revise various portions of the new project proposal.

Revisions will be sent to T. Paulitz for compilation and submission.

Prior to meeting adjornment at 5PM, the members expressed their thanks to J. Borneman for his fine job in making local arrangements.


Submitted: Gary Yuen

Accomplishments

<b>Objective 1. To identify and characterize new biological agents, naturally suppressive soils, cultural practices, and organic amendments that provide control of diseases caused by soilborne plant pathogens.</b><br /> <br /> <b>CA-R-</b> In a Southern California survey for sugar beet suppressive soils, only two of about 50 agricultural field soil samples showed significant suppressiveness against <i>H. schachtii.</i> <br /> <br /> <b>CA-R-</b> A sterile nematophagous fungus (ARF) with biocontrol activity against cyst nematodes and morphology resembling <i>D. oviparasitica</i> was the subject of a series of investigations at the University of Arkansas starting in the 1990s. Our analysis of the 5.8S rRNA gene from ARF indicated that the strain is indeed closely related to <i>D. oviparasitica</i> strain 50. Preliminary data from a survey of sugar beet fields in Southern California indicate that related fungi might be more abundant than previously thought. <br /> <br /> <b>CA-R-</b> We investigated effects of soil pH on damping-off of sugar beet by the soilborne fungus <i>R. solani</i> (AG2-2). Soil suppressiveness against the disease were studied by comparing disease incidence in pasteurized and non-pasteurized infested soils. Indigenous disease suppressiveness through the activity of antagonistic soil microorganisms functioned well in alkaline soils, but less or not at all in acidic soils.<br /> <br /> <b>CA-R-</b> We determined the relationships between the amounts of the fungus <i>Dactylella oviparasitica</i> and the plant-parasitic nematode <i>Heterodera schachtii</i>, toward the goal of developing a more effective tool for making sugar beet planting decisions.<br /> <br /> <b>CA-R-</b> We performed a high-throughput sequencing analysis of rRNA genes to identify bacteria associated with peach disease symptoms of peach. This worked identified a list of potentially causal agents.<br /> <br /> <b>CA-R</b> We discovered a new endomycorrhizal fungus (molecularly identified as an Ascomycete) which is culturable, and, in preliminary studies, enhances growth of plants in the Brassicae family. <br /> <br /> <b>CA-R</b> We determined that the tripartite host-specific interaction between <i>Olpidium bornovanus</i> and <i>Monosporascus cannonballus</i> is dependent upon near-saturated soil moisture conditions. <br /> <br /> <b>IL-</b> A project to evaluate the effect of various fall planted cover crop treatments on diseases in subsequent soybean crops was initiated in the fall of 2010. Fall planted cover crop treatments included cereal rye, rape, canola, white mustard, and winter fallow. Plots were established at six locations in Illinois. At each location cover crops were planted in the fall of 2010 and 2011, with rye, rape, and fallow treatments at the on-farm locations; and all five treatments at the on-station locations. Soil samples were collected in the fall of 2010 (to establish baseline values), and again in the spring of 2011 and spring of 2012, shortly after planting the soybean crop, two to three weeks after incorporation of the cover crop debris. Sub-samples of the soils were taken and used for determining population levels of soybean cyst nematodes (SCN) and for DNA extraction. The DNA extracts are being used to determine population levels of selected soybean pathogens through QPCR and for ARISA analysis to establish microbial community profiles for each soil sample. The remainder of the soil sample for each plot is being used for greenhouse bioassays to evaluate the disease suppressiveness of the soils to selected soybean pathogens (<i>Fusarium virguliforme</i> and <i>Rhizoctonia solani</i>) for each cover crop treatment. <br /> <br /> <b>IL-</b> At the on-station location in east-central Illinois, treatments also included pathogen infestation of sub-plots with <i>Fusarium virguliforme</i> (the causal agent of sudden death syndrome of soybean) and <i>Rhizoctonia solani</i> (the causal agent of Rhizoctonia seedling blight and root rot). In 2011, early season stand counts showed that seedling damping-off levels were extremely high in the <i>Rhizoctonia solani</i> infested sub-plots of the fallow and mustard cover crop treatments, while damping-off levels in the rye cover crop plots were very low, similar to those in the non-infested plots. Damping-off levels in the canola and rape treatment plots were intermediate in severity between the fallow and rye treatment plots. In 2012, stand counts in the Rhizoctonia infested plots were not significantly different from the non-infested plots. However, lesion lengths of typical Rhizoctonia lesions on the hypocotyl/radical were longest on plants growing in the fallow plots and shortest on the plants growing in the rye plots. No significant differences were seen in levels of sudden death syndrome symptoms in the <i>Fusarium virguliforme</i> infested sub-plots in either 2011 or 2012. Levels of soilborne-root diseases at the other locations were fairly low, and no differences associated with cover crop treatment were observed in 2011 or 2012. <br /> <br /> <b>MI-</b> Research on potato-common-scab suppressive soil was continued. A bacterium <i>Bacillus amyloliquefaciens</i> strain BAC03 isolated from this soil was studied for biological control on potato common scab. This strain has been patented and a progress is on going for commercialization. Field results showed that this product is effective in controlling potato common scab. This study has been published. <br /> <br /> <b>NM-</b> In a greenhouse study, mustard seed meal was used at the rate of 0, 1000, or 2000 pounds per acre. Seed germination was similar in all treatments, although it was delayed for 3-5 days in soil treated with mustard seed meal. The highest percentage of chile plant survival was achieved in soil treated with mustard seed meal and covered with clear plastic for 3 weeks before planting. <br /> <br /> <b>NM</b>- In a chamber study two microbial formulations, approved for organic production, were applied to soil as an aqueous solution (2 g/liter), one (Piranha) containing a combination of nine fungal species including mycorrhizae (<i>Trichoderma</i> spp, <i>Glomus</i> spp, and <i>Rhizopogon</i> spp.) and two species of bacteria (<i>Pseudomonas</i> spp.), and the other (Tarantula) containing a combination of bacteria including nine species of <i>Bacillus</i>. Pots were infested with <i>Phytophthora capsici</i> one week after sowing. None of the formulations prevented seedling infection and mortality by <i>P. capsici</i>. However, using biorational products containing multiple microbial species is an ecologically sound approach in the control of soilborne pathogens, and necessitates further research. <br /> <br /> <b>NY</b>- The development of our symbiotic multifunctional plant symbiotic Trichoderma strains took a major step forward in this past year. Sales of products based on these organisms have increased rapidly especially in the Midwest, on crops such as corn, soybeans and wheat. Their abilities to increase drought resistance was very much on display this past year. Even though the strains are applied as seed treatments, their abilities to colonize roots for the life of at least an annual crop was important. The increase in return on investment to corn growers is about 6:1 and is higher than that for wheat and soybean growers. In several hundred field trials over the past four years, the yield increase for corn is about 8.5 bushels. In the year of drought, the yield increase was about 10 bushels. The strains and products based upon them are now registered and available for sale in 11 other countries with 15 more where registrations are close to complete. <br /> <br /> <br /> <b>NY-</b> Assessing the impact of selected cover crops on root health, soil health and crop productivity: This is a collaborative research and outreach project between NY, PA, and CT with funding support from the NE-IPM program. In New York, the final evaluation of the 9 cover crop treatments (rye grain + hairy vetch, oat, sudex, forage radish, red clover, rapeseed, buckwheat, wheat, and a fallow/control) that were established in four fields with different management histories in 2009 (total of 108 plots) was completed in 2012. Marketable yield of bean varied among the cover crop treatments and was influenced by the previous management strategies employed (four production systems tested) and also years. However, the lowest bean yields were generally in the buckwheat and the fallow check, whereas the highest yield fallowed primarily the rye/vetch, wheat, and oat. Weed pressure was least in the rye/vetch, wheat, and rapeseed plots, whereas weeds where the most severe in the fallow/check, buckwheat, and sudex plots. In addition, Buckwheat, clover and the fallow check appeared to increase root rot severity of beans in this evaluation. In contrast, the lowest accumulated increases in root rot severity over the duration of the study were in the wheat, sudex, oat, and radish plots. Many studies have shown that cover crops differ greatly in their suppression of various root pathogens as well as other soil management practices. <br /> <br /> <b>OR-</b> Management of <i>Phytophthora</i> spp. in recirculating irrigation water in nurseries: Nurseries often capture and reuse irrigation water, but this water can become a source of contamination by plant pathogenic oomycetes such as <i>Pythium</i> and <i>Phytophthora</i> spp. We investigated the viability and infectivity of <i>Phytophthora pini</i> zoospores in a simulated recirculating irrigation water system. Results using a detached leaf assay demonstrated that zoospores which encysted during passage through a pressure-nozzle system were less capable of causing foliar lesions on rhododendon than were non-encysted zoospores. Encysted zoospores caused disease on only on wounded leaves, whereas non-encysted zoospores also infected non-wounded leaves.<br /> <br /> <b>WA-</b> Taxa in Oxalobacteriaceae- <i>Massillia, Herbaspirillum, Duganella</i>) and <br /> Sphingobacteria- (<i>Chyseobacterium, Pedobacter,</i> Chitinophagaceae) were associated with the rhizosphere of diseased plants inside of Rhizoctonia bare patches on wheat, in a field undergoing Rhizoctonia decline. Isolates of <i>Chyseobacterium</i> were effective in controlling Rhizoctonia root rot of wheat in greenhouse tests with inoculated soil. These same groups were associated with wheat roots of plants grown in Rhizoctonia suppressive soils from 3 locations in Australia.<br /> <br /> <b>WA-</b> A large collection of <i>Rhizoctonia</i> was made from dryland wheat fields in eastern Washington, covering an area of 100s of square kilometers. This is the same area with high levels of phenazine producing <i>Pseudomonas</i>. We tested the hypothesis that Rhizoctonia may have co-evolved with these strains, and developed resistance or tolerance to this antifungal compound. But there was no difference in sensitivity to phenazine between <i>Rhizoctonia</i> strains collected from areas with high frequency of phenazine producers, compared to areas with a low frequency. For both <i>R. solani</i> AG-8 and AG 2-1, the ED50 was around 10 ppm.<br /> <br /> <b>WA</b>- Comparative genomics and bioinformatics are underway on eleven new strains of <i>Pseudomonas</i>, originating from collaborator Chris Taylor, that control nematodes and fungal soilborne pathogens. Sequence data was obtained and assembled using Velvet by The Ohio State University, and annotated using a pipeline developed by the Chang group. Seven strains that have been provisionally annotated cluster with other biocontrol pseudomonad in the Pf-5, Pf01, SBW25 and NFM421 subclades, and each contain unique DNA.<br /> <br /> <b>Objective 2 To understand how microbial populations and their gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease.</b><br /> <br /> <b>IL-</b> DNA extracts from the cover crop treated soils was analyzed to quantify population levels of selected soybean pathogens to determine if the cover crop treatments directly suppress (or possibly increase) pathogen populations. Initial analysis of this data indicates that pathogen population levels were not significantly different as a result of the cover crop treatments. DNA extracts were also used develop microbial community profiles using the ARISA technique to determine if microbial populations shift as a result of the cover crop treatments. Differences in microbial populations were observed between the various locations of the study, but no differences were observed resulting from the cover crop treatments. The ARISA technique evaluates the overall microbial community structure. It is possible that changes in small sub-groups within the larger microbial community are changing in response to cover crop treatments, and that these are responsible for the disease suppressive effects observed. <br /> <br /> <b>MI-</b> Compatibility of biocontrol agent <i>Coniothyrium minitans</i> with fungicides, fertilizers, and herbicides were studied. This study was to provide information about the survival of <i>C. minitans</i> in the field and the feasibility of tank mix. Biological control products, including chestnut tissues, and oregano essential oil, <i>Coniothyrium minitans</i> (Contans, SipcamAdvan), <i>Streptomyces lydicus</i> (Actinovate, SipcamAdvan), and <i>Trichoderma gamsii</i> and <i>T. asperellum</i> mixture (Tenet, SipcamAdvan), were studied for managing soybean white mold and potato common scab under greenhouse and field conditions in Michigan. Cover crops have been studied in the field to determine the effect of disease management, and soil microbial community is being analyzed in response to the effect. <br /> <br /> <b>NE-</b> Previous research on <i>Lysobacter enzymogenes</i> strain C3, a biocontrol agent of fungal and nematode plant pathogens, demonstrated production of HSAF (a family of macrocyclic lactams including dihydromaltophilin) to be an important biocontrol mechanism. HSAF biosynthetic genes in C3 were identified, as was a global regulatory gene <i>clp</i>. A study was initiated in 2012 to identify additional genes involved in antimicrobial secondary metabolite production in the strain. Thirty seven putative genes with domains involved in two-component signal transduction systems were identified, and insertion or deletion mutants were constructed for each gene. Preliminary analysis of HSAF production using HPLC revealed 7 to be reduced in HSAF production compared to wildtype C3. In contrast, one mutant strain (1909) produced over 3-fold higher levels of HSAF than the wildtype in repeated experiments. The gene deleted in 1909 is homologous to <i>pilG</i> which codes for a two-component system regulatory protein in strains of <i>Xanthomonas</i> spp. and <i>Xyllela fastidiosa. PilG</i> has been reported to up-regulate production of type 4 pilus (T4P) involved in gliding motility in other bacterial species. The involvement of the C3 <i>pilG</i> homolog in T4P production was supported by reduced gliding motility in mutant strain 1909. However, this is the first connection found between regulation of T4P and production of antimicrobial secondary metabolites.<br /> <br /> <b>OR-</b> Regulation of microbial populations by plants, and how plants and microbes influence disease: <i>Striga</i>, a genus of obligate parasitic weeds in the family Orobanchaceae, has been identified as the most important biological factor limiting agricultural productivity in sub-Saharan Africa. Germination of <i>Striga</i> seeds is triggered by strigolactone root exudates from host plants. Strigolactones also induce hyphal branching in arbuscular mycorrhizal (AM) fungi, which are important for plant uptake of phosphorus in low phosphorus soils. Mechanisms of <i>Striga</i> resistance based on reduced strigolactone production may also convey resistance to AM fungi which would require higher inputs of phosphorus fertilizer to attain optimal crop growth. There is evidence for genetic differences in mycorrhizal responsiveness in other grain crops; therefore it is beneficial for breeders to be aware of these differences when developing <i>Striga</i>-resistant sorghum cultivars. We conducted research to determine phosphorus and mycorrhizal responsiveness of sorghum genotypes important for or developed by breeders working on <i>Striga</i> resistance. Phosphorus response curves were determined for twelve sorghum genotypes using pasteurized low phosphorus soil amended to achieve four different phosphorus levels. Simple linear regression was performed on root and shoot dry weight data. Results indicate variability in phosphorus responsiveness within <i>Striga</i> resistant and susceptible genotypes. Seven of these genotypes were selected for continued research, which analyzed responsiveness to phosphorous and differences in mycorrhizal responsiveness in relation to reported mechanisms of Striga resistance. All seven genotypes were responsive to mycorrhizae, with a significant increase in biomass for all genotypes, especially at the lowest phosphorus level. The responsiveness to the mycorrhizal fungus does not appear to be directly related to the susceptibility of genotypes to the parasitic weed <i>Striga</i>.<br /> <br /> <b>Objective 3. To implement sustainable management strategies for soilborne pathogens that are biologically based and compatible with soil health management practices.</b><p><br /> <br /> <b>CA-R-</b> Avicta seed coating provided consistent early season protection against root-knot nematodes in several carrot field trials during 2010-2012. The product's active ingredients are metabolites of <i>Streptomyces avermitilis</i>. Combination of Avicta with live biocontrol bacteria or fungi is possible as the a.i. has no known antimicrobial activity. In greenhouse tomato trials with <i>M. incognita</i>, the combination of Avicta with <i>Pochonia chlamydosporia</i> was superior to either treatment alone in reducing the nematode population (J2) and root galling as well as in increasing plant weight. Similar results were obtained in microplot trials with a Avicta/Pasteuria penetrans combination.<br /> <br /> <b>CA-R-</b> Several botanical and microbial products were tested for purported nematicidal activity against root-knot nematodes. In an assay designed to detect egg parasitic activity against <i>Meloidogyne incognita</i>, MeloCon (<i>Paecilomyces lilacinus</i> 251) reduced the root-knot nematode population by approximately 30% at 23ÚC but had no effect at lower or higher temperatures. In tomato greenhouse trials MeloCon did not reduce juvenile population density or root gall disease. In field trials NemaQ, Actinovate, Sesamin EC, Dazitol, Ecozin Plus, and Nortica failed to show significant efficacy against <i>M. incognita</i> as indicated by root gall ratings after 8 weeks and 12 weeks (harvest).<br /> <br /> <b>OR-</b> Soil solarization to manage soilborne Phytophthora spp.: In 2012 we conducted field trials in CA and OR to investigate the effectiveness of soil solarization and biocontrol, alone or together, in disinfesting soil containing inoculum of <i>Phytophthora</i> spp. Infested leaf inoculum of <i>Phytophthora ramorum</i> containing hyphae and chlamydospores was buried in a compacted soil. Soil temperature and moisture were continuously monitored. In the first trial, no <i>P. ramorum</i> was recovered from solarized plots after four weeks, where average soil temperatures were 36.9°C, 35.3°C, and 33.3°C, respectively. In contrast, <i>P. ramorum</i> was recovered from all three depths from the non-solarized plots where average temperatures were 27.6°C, 27.3°C, and 27.0°C at 5, 15, and 30 cm respectively. A subsequent trial in August-Sept., 2012 showed that as little as two weeks of solarization was effective in eliminating <i>P. ramorum</i> from the 5 cm and 15 cm depths, where the majority of <i>P. ramorum</i> is located in nurseries. After solarization, the biocontrol amendment <i>Trichoderma asperellum</i> TA1was added to half of each solarized and non-solarized plot. The results from the biocontrol amendment are still pending. We hypothesize that prior solarization of the soil will enhance the establishment of the biocontrol agent, which could provide sustained protection after the pathogen has been killed by solarization. Analysis of temperature parameters impacting pathogen survival, including the degree-hours above a certain temperature, is underway.<br /> <br /> <b>OR-</b> A pilot solarization study was also conducted in two commercial nurseries in Oregon that were naturally infested with <i>Phytophthora</i> species. The commercial nurseries differed from the NORS-DUC site in that a several centimeter thick layer of rock or gravel, typical of a container yard, overlaid (and was partially embedded in) the soil. Soil/rock/gravel was sampled from 0-5 cm and from 5-10 cm below the surface before and after solarization which began in early September, and 4 wks after application of amendment with either <i>Trichoderma asperellum</i> TA1, SoilGard, or no amendment. The soil temperatures achieved in these commercial nurseries in Oregon were lower than those achieved at NORS-DUC; nevertheless, <i>Phytophthora</i> recovery was drastically reduced by solarization alone in one nursery, and by the combination of solarization and biocontrol in the other nursery. No plant pathogenic <i>Phytophthora</i> species were recovered in either nursery in solarized soil amended with either of the biocontrol treatments. <br /> <br /> <b>NY-</b> Documenting the influence of soil health management strategies on root disease severity: The on-going, large-scale experiment (14 acres) conducted in collaboration with the Soil Health Program Work Team at Cornell was continued in 2012. The trial was established in 2003 at the long-term soil health site at the Gates Farm near Geneva, NY. The 18 treatments of the experiment include three tillage systems (no-till, strip-till, and conventional tillage), three cover crops (rye grain, hairy vetch, and no cover/fallow) and two rotations (one heavy with vegetables, whereas the other includes grain and forage crops and less vegetables. The 2012 results of the root rot severity assessment (soil bioassay with beans in the greenhouse) showed only small differences among the production treatments. However, the lowest root rot ratings were those of the plots with reduced tillage (strip-till and no-till) and the rotation with frequent grain and forage crops. In 2011, all the plots were planted to snap bean cv. Caprice (indexing crop planted every 3-4 years) to assess the accumulated effects of the tested treatments and their combinations. Results obtained showed that pod yield was highest in the ridge-till and in the zone-till plots and was lowest in the plow-till plots. In addition, it was difficult to machine harvest the plow-till plots due to excessive rainfall during the growing season, but there was no problem harvesting the reduced tillage plots and also the ridge-till plots. Root rot severity assessment in the field and in the greenhouse bean bioassay did not differ greatly among the various treatments, but it was again lower on roots of plants grown in the ridge-till plots.<br /> <br /> <b>WA-</b> Rhizoctonia bare patch of onions is caused by <i>R. solani</i> AG-8, and is a major problem in irrigated circles in the Columbia Basin. The disease is exacerbated by a wheat cover crop that is planted for the fall and winter to hold the sand and keep it from blowing. The pathogen greenbridges from the dying cover crop to the newly seeded onion crop. We tested different timings of cover crop sprayout, and found significantly less disease when the wheat was sprayed out 17 or 27 days before planting, compared to 3 days before planting. This may be a useful tool in management of this disease. <br /> <br /> <b>Objective 4. Provide outreach, education, extension and technology transfer to our clients and stakeholders- growers, biocontrol industry, graduate and undergraduate students, K-12 students and other scientists.</b><p><br /> <br /> <b>IL-</b> The Illinois cover crops project described above includes a significant outreach component that will be implemented in the third year of the project, once results have been obtained and analyzed. Descriptions of the project have already been distributed in the form of news releases and popular press articles. <br /> <br /> <b>MI-</b> Results of the research were disseminated to soybean and potato growers, farm advisors, industry personnel and professional researchers at various meetings and conferences. <br /> <br /> <b>NE-</b> Gary Yuen at University of Nebraska-Lincoln co-taught a distance-delivered course Biological Control of Pests that reached 58 graduate students located throughout the nation involved in plant health disciplines. Yuen also taught Introductory Plant Pathology to more than 70 undergraduate students, presenting biological control as a critical component of integrated disease management. In both courses, examples of research and implementation from W2147 members were used to illustrate these facets. <br /> <br /> <b>OR-Talks for growers:</b> Parke gave invited talks to 100 growers and agricultural professionals at the UC Nursery and Floriculture Alliance: Nursery/Floriculture Disease Management Symposium in Watsonville, CA on the theory and practice of systems approaches, and on methods for disinfesting irrigation water. She also gave an invited talk on systems approaches for managing nursery diseases and pests at the NW Ag Show in Portland, OR sponsored by the Oregon Association of Nurseries (55 participants). <br /> <br /> <b>OR-Websites maintained<br><br /> Forest Phytophthoras of the World</b> www.ForestPhytophthoras.org<br><br /> Plant pathogens in the genus <i>Phytophthora</i> threaten the biodiversity and sustainability of forest ecosystems worldwide. The overall aim of this website is to provide science-based information to aid in the understanding and management of the worlds forest <i>Phytophthora</i> species, all of which have a soilborne phase. While newly emerging, damaging species are the highest priority, information on other Phytophthoras is included in an attempt to gradually elucidate Phytophthoras diverse roles in terrestrial and aquatic ecosystems.<p><br /> <br /> <b>OR-Online Phytophthora Course: Training for Nursery Growers</b><br> http://oregonstate.edu/instruct/dce/phytophthora/index.html This free, online course is intended to inform nursery growers on ways to reduce their risk of <i>Phytophthora</i> disease in their nurseries. Available in both English and Spanish language versions, the course consists of three modules: biology and symptoms, disease management, and <i>Phytophthora ramorum</i>. The course is free, but there is an optional online exam which participants may take for $100. If they pass the test, they receive a Certificate of Mastery on <i>Phytophthora</i> from Oregon State University Extended Campus and are eligible for four credits of pesticide recertification credits through the Oregon Department of Agriculture.<p><br /> <br /> <b>OR-Journal edited<br><br /> <i>Forest Phytophthoras,</b></i>, http://journals.oregondigital.org/ForestPhytophthora/issue/current is an open access, peer-reviewed, online journal. This journal provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge. Published articles are permanently archived with a unique digital object identifier (doi). Articles are available as html files and pdf files.<br /> <br /> <b>OR-Graduate student mentoring:</b> Parke mentored five graduate students in 2012, including three who completed their M.S. theses in plant pathology or soil science. Parke served on three additional graduate student committees, including one at the Univ. of Florida.<br /> <br /> <b>OR-Technology transfer and policy development:</b> Parke was invited to chair a national technical working group (TWG) of plant pathologists, entomologists, and horticulturalists by the APHIS Systems Approach Program Partnership. The TWGs charge was to evaluate plant production practices to enhance the ability of greenhouse and nursery operations to produce healthy plants. Specifically, the TWG identified practices and procedures that should be incorporated into a systems approach utilizing critical control points and associated best management practices to mitigate pests and pathogens. These BMPs will be used to identify standards that APHIS views as being important to greenhouse and nursery stock production and which may serve as a foundation for phytosanitary certification for use by harmonized state-based nursery certification programs. The output consisted of an unpublished document Matrix of minimum best management practices for producing healthy greenhouse and nursery plants delivered to APHIS in summer, 2012. This document is currently undergoing review by nursery and greenhouse stakeholders and the National Plant Board for possible adoption by APHIS. <br /> <br /> <b>NY-</b> Sustainable management of root diseases and soil health: A number of participatory training workshops on the identification, assessment and management of soilborne plant pathogens in vegetable production systems were conducted by Abawi and Smart, in NY, PA, and MI.<p><br /> <br /> <b>NY-</b> Undergraduate research experience. The Plant Pathology and Plant-Microbe Biology Department on the Geneva Campus of Cornell University established a summer scholars program to increase the involvement of undergraduate researchers in applied agricultural sciences. Smart is the director of this program for all 4 departments on the campus. In 2012, 28 students presented posters at the end of the program. Each summer, several students are involved with projects that are part of the W2147 multi-state project. During the summer of 2012, three students in the Smart lab were working on <i>Phytophthora capsici</i> detection in 1) irrigation water and 2) tomato plant rhizosphere samples and the third student worked on the population biology and evolution of the pathogen. Additionally, an undergraduate student in the Abawi lab worked on nematode problems in garlic.<br /> <br /> <b>NY-</b> Outreach to K-12 students. We have continued our outreach program to third-grade students in the Geneva City School District (Geneva, NY). Part of this outreach includes a summer science camp, where students study different aspects of food production utilizing a garden that they plant at their school. One week of the 5-week program focuses on the importance of healthy soil to producing healthy vegetables.<br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />

Publications

<b>Refereed Publications and Abstracts</b><br /> <br /> <br /> Abawi, G. S., K. Moktan, C. Stewart, R. Hadad, and C. Hoepting. 2012. Current status of the bloat nematode on garlic in New York. Journal of Nematology 44: (in-press). Poster presented at the SON Annual meeting held in Savannah, GA during August 12  15, 2012.<br /> <br /> Balaji, V. and Smart, C.D. 2012. Over-expression of snaking-2 and extension-like protein genes restricts pathogen invasiveness and enhances tolerance to Clavibacter michiganensis subsp. michiganensis in transgenic tomato (Solanum lycopersicum). Transgenic Research 21:23-37.<br /> <br /> Becker, J.O., A. Ploeg, and J. Nunez 2012. Evaluation of novel products for root knot nematode management in tomato, 2011. Plant Disease Management Report No. 6:N016.<br /> <br /> Cai, G., Restrept, S., Myers, K.L., Zuluaga, P., Danies, G. Smart, C.D. and Fry, W.E. 2013. Gene profiling in partially resistant and susceptible near-isogenic tomatoes in response to late blight in the field. Molecular Plant Pathology in press.<br /> <br /> Dunn, A.R. and Smart, C.D. 2012. Monitoring changes in population structure of an isolated research population of Phytophthora capsici. Phytopathology 102:S4.32 (abstract).<br /> <br /> Escobar, C., and Hao, J. 2012. Assessing biological control agents and their fungicide sensitivities for potential integrated management of Sclerotinia stem rot in soybean. Phytopathology 102:S5.4. (Abstract) <br /> <br /> Fry, W.E., McGrath, M.T., Seaman, A., Zitter, T.A., McLeod, A., Danies, G., Small, I.M., Myers, K., Everts, K., Gevens, A.J., Gugino, B.K., Johnson, S.B., Judelson, H., Ristaino, J., Roberts, P., Secor, G., Seebold, K., Snover-Clift, K., Wyenandt, A., Grunwald, N.J., and Smart, C.D. 2013. The 2009 late blight pandemic in Eastern USA  causes and results. Plant Disease in press.<br /> <br /> Gachango, E., Hanson, L. E., Rojas, A., Hao, J. J., and Kirk, W. W. 2012. Fusarium spp. causing dry rot of seed potato tubers in Michigan and their sensitivity to fungicides. Plant Disease. Accepted. <br /> <br /> Hao, J. J., Donis-Gonzalez, I. R., Jiang, H. H., and Fulbright, D. W. 2012. Antimicrobial activity in chestnut tissues corresponding with flavonol glycoside and terpenoid substances. The 5th International Chestnut Symposium. Shepherdstown, WV. Sep. 4 to 8. (abstract)<br /> <br /> Jiang, H. H., Meng, Q., Hanson, L. E., and Hao, J. J. 2012. First report of Streptomyces stelliscabiei causing potato common scab in Michigan. Plant Disease 96:904.<br /> <br /> Jones, L.A., Worobo, R.W. and Smart, C.D. 2012. Oomycete and bacterial pathogens in New York surface irrigation water: Survey results and ultraviolet treatment. Phytopathology 102:S4.60 (abstract).<br /> <br /> Jones LA, Worobo RW, and Smart CD. 2012. Ultraviolet Treatment of Pathogens in Surface Irrigation Water. Abstracts of the Human Pathogens on Plants Workshop p17-18 (abstract).<br /> <br /> Kim, S.-D., De La Fuente, L., Weller, D. M., and Thomashow, L. S. 2012. Colonizing ability of Pseudomonas fluorescens 2112, among collections of 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens spp. in pea rhizosphere. Journal of Microbiology and Biotechnology 22:763-770.<br /> <br /> Kwak Y-S, Bonsall RF, Okubara PA, Paulitz TC, Thomashow LS, Weller DM (2012) Factors impacting the activity of 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens against take-all of wheat. Soil Biol Biochem 54: 48-56.<br /> <br /> Lee, H., Ullrich, S. E., Burke, I. C., Yenish, J. and Paulitz, T. C. 2012. Interactions between the root pathogen Rhizoctonia solani AG-8 and acetolactate-synthase-inhibiting herbicides in barley. Pest Management Science 68 :845-852.<br /> <br /> Lange, H.W. and Smart, C.D. 2012. Evaluating efficacy of black rot control caused by Xanthomonas campestris pv. campestris in greenhouse transplant production. Phytopathology 102:S4.66 (abstract)<br /> <br /> Liebhold, A. M., Brockerhoff, E. G., Garrett, L. J., Parke, J. L., and Britton, K. O. 2012. Live plant imports: the major pathway for forest insect and pathogen invasions of the US. Frontiers in Ecology and the Environment 10: 135143. http://dx.doi.org/10.1890/110198<br /> <br /> Loper JE, Hassan KA, Mavrodi DV, Davis EW, Lim CK, Shaffer BT, Elbourne LDH, Stockwell VO, Hartney SL, Breakwell K, Henkels MD, Tetu SG, Rangel LI, Kidarsa TA, Wilson NL, van Mortel JE, Song C, Blumhagen R, Radune D, Hostetler JB, Brinkac LM, Durkin SA, Kluepfel DA, Wechter PW, Anderson AJ, Kim YC, Pierson LS, Pierson EA, Lindow SE, Kobayashi DY, Raaijmakers JM, Weller DM, Thomashow LS, Allen AE, and Paulsen IT 2012. Comparative genomics of plant-associated Pseudomonas spp: insights into diversity and inheritance of traits involved in multitrophic interactions. PLoS Genetics 8: e1002784<br /> Lu, X. H., Davis, R. Michael, Livingston, S., Nunez, J. J., Hao, J. J. 2012. Fungicide sensitivity of Pythium species associated with cavity spot of carrot in California and Michigan. Plant Disease 96:384-388.<br /> <br /> Maketon C, Fortuna A-M, Okubara PA 2012. Cultivar-dependent transcript accumulation in wheat roots colonized by Pseudomonas fluorescens Q8r1-96 wild type and mutant strains. Biol Cont 60: 216-224.<br /> <br /> Mastouri, F., T. Bjorkman and G. E. Harman, 2012. Trichoderma harzianum strain T22 enhances antioxidant defense of tomato seedlings and resistance to water deficit. Molec. Plant Microbe Interact. 25, 1264-1271.<br /> <br /> Mavrodi DV, Mavrodi OV, Parejko JA, Bonsall RF, Kwak Y-S, Paulitz TC, Thomashow LS, and Weller DM 2012. Accumulation of the antibiotic phenazine-1-carboxylic acid in the rhizosphere of dryland cereals. Applied and Environmental Microbiology 78: 804-812<br /> Mavrodi OV, Mavrodi DV, Parejko JA, Thomashow LS, and Weller DM 2012. Irrigation differentially impacts populations of indigenous antibiotic-producing Pseudomonas spp. in the rhizosphere of wheat. Applied and Environmental Microbiology 78: 3214-3220 highlighted in the June 2012 issue of Microbe magazine published by the American Society for Microbiology. <br /> Mavrodi OV, Walter N, Elateek S, Taylor CG, Okubara PA 2012. Suppression of Rhizoctonia and Pythium root rot of wheat by new strains of Pseudomonas. Biol Cont 62: 93102<br /> <br /> Mavrodi, D. V., Mavrodi, O. V., Parejko, J. A., Bonsall, R. F., Kwak, Y. S. Paulitz, T. C., Thomashow, L. S. and Weller, D. M. 2012. Accumulation of the antibiotic phenazine-1-carboxylic acid in the rhizosphere of dryland cereals. Applied and Environmental Microbiology 78: 804-812. <br /> <br /> Meng, Q. Yin, J. F., Rosenzweig, N., Douches, D., and Hao, J. J. 2012. Culture-based assessment of microbial communities in soil suppressive to potato common scab. Plant Disease 96: 712-717. <br /> <br /> Meng, Q., Jiang, H. H., Hanson, L. E., and Hao, J. J. 2012. Characterizing a novel strain of Bacillus amyloliquefaciens BAC03 for potential biological control application. Journal of Applied Microbiology. Journal of Applied Microbiology 113: 1165-1175.<br /> <br /> Parejko JA, Mavrodi DV, Mavrodi OV, Weller DM, and Thomashow LS 2012. Population structure and diversity of phenazine-1-carboxylic acid producing fluorescent Pseudomonas spp. from dryland cereal fields of central Washington State (USA). Microbial Ecology 64: 226-241 <br /> <br /> Parke, J. L. and N. J. Grünwald. 2012. A systems approach for management of pests and pathogens of nursery crops. Plant Dis. 96:1236-1244. http://dx.doi.org/10.1094/PDIS-11-11-0986-FE<br /> Paulitz, T. C., Cook, R. J., Campbell, K.G. and Poole, G. 2012. Fusarium crown rot research in the Pacific Northwest of the United States: A half a century of discoveries. Pg. 11. Proceedings of the First International Crown Rot Workshop for Wheat Improvement, Oct. 22-23, 2012. Narrabri, New South Wales, Australia. <br /> Ploeg, A., J.O. Becker, and J. Nunez 2011. Integrated control of root-knot nematodes in California carrot. J. Nematology 43: 271. (abstract).<br /> <br /> Pokharel, R. R., G. S. Abawi, and J. M. Duxbury. 2011. Greenhouse evaluation of rice and wheat germplasms for resistance to Meloidogyne graminicola with comments on evaluation indices and proposal of a new one. Nematologia Mediterranea 39: 157  168.<br /> <br /> Poole, G. J., Erginbas, G., Smiley, R. W., Campbell, K. G. and Paulitz, T. C. 2012. Inoculation methods to assay wheat seedlings for resistance to Fusarium crown rot in a controlled environment. Pg. 39. Proceedings of the First International Crown Rot Workshop for Wheat Improvement, Oct. 22-23, 2012. Narrabri, New South Wales, Australia.<br /> Poole, G. J., Smiley, R. W., Paulitz, T. C, and Campbell, K. G. 2012. Identifying QTL for Fusarium crown resistance (F. pseudograminearum) in field, terrace, and growthroom screen environments. Pg. 49. Proceedings of the First International Crown Rot Workshop for Wheat Improvement, Oct. 22-23, 2012. Narrabri, New South Wales, Australia.<br /> <br /> Poole, G. J., Smiley, R. W., Paulitz, T. C., Walker, C. A., Carter, A. H., See, D. R. and Garland-Campbell, K. 2012. Identification of quantitative trait loci (QTL) for resistance to Fusarium crown rot (Fusarium pseudograminearum) in multiple assay environments in the Pacific Northwestern US. Theoretical and Applied Genetics 125: 91-107. <br /> <br /> Poole, G. J., Smiley, R. W., Walker, C. A., Campbell, K. G., and Paulitz, T. C. 2012. Distribution of Fusarium spp. causing crown rot in the Pacific Northwest. Pg. 22. Proceedings of the First International Crown Rot Workshop for Wheat Improvement, Oct. 22-23, 2012. Narrabri, New South Wales, Australia.<br /> <br /> Rosenzweig, N., Lu, X. H., Jiang, H., and Hao, J. 2012. Multigene analysis of Pythium species causing carrot cavity spot in California and Michigan. Phytopathology 102:S4.102. (abstract)<br /> <br /> Rosenzweig, N., Tiedje, J., Quensen III, J. Meng, Q., and Hao, J. J. 2012. Microbial communities associated with potato common scab suppressive soil determined by pyrosequencing analyses. Plant Disease 96: 718-725. The Editors Pick. <br /> <br /> Schroeder, K. L. and Paulitz, T. C. 2012. First Report of a Ceratobasidium sp. causing root rot on canola in Washington State. Plant Disease 96: 591.<br /> <br /> Schroeder, K. L. and Paulitz, T. C. 2012. First report of root rot caused by Rhizoctonia solani AG-10 on canola in Washington State. Plant Disease 96: 584.<br /> <br /> Smith Becker, J., J. Yang, J. Borneman, P. Timper, R.R. Riggs, and J.O. Becker 2011. Investigations into the relatedness of the nematophagous fungi Dactylella oviparasitica and ARF-L. J. Nematology 43: 228. (abstract)<br /> <br /> Sanogo, S., and Ji, P. 2012. Integrated management of Phytophthora capsici on solanaceous and cucurbitaceous crops: current status, gaps in knowledge, and research needs. Canadian Journal of Plant Pathology 34: 479492.<br /> <br /> Sanogo, S., Roth, B., Liess, L., and Grover, K. 2012. Effect of two soil inoculants on seed germination and infection of chile seedlings by Phytophthora capsici. Phytopathology 102:S6.12 (abstract)<br /> <br /> Sanogo, S., and Schaub, T. 2012. Evidence of inhibitory volatiles of London rocket and flixweed against three soilborne pathogens of chile pepper. Phytopathology 102:S6.12 (abstract).<br /> <br /> Summers, C.F., Smart, C.D., McSpadden Gardener, B.B., Everts, K.L., Dunn, A.R. and Park, S. 2012. The impact of mixed-species cover crops on rhizosphere pathogens of organically managed tomato crops in New York, Ohio, and Maryland. Phytopathology 102:S4.115 (abstract)<br /> <br /> Tancos, M.A., Small, I.M., Fry, W.E., and Smart, C.D. 2012. Early detection of airborne inoculum from wind-disseminated oomycetes. Phytopathology 102:S4.118 (abstract)<br /> <br /> Watanabe, K., M. Matsui, H. Honjo, J.O. Becker, and R. Fukui 2011. Effects of soil pH on Rhizoctonia damping-off of sugar beet and disease suppression induced by soil amendment with crop residues. Plant Soil 347:255-268.<br /> <br /> Weerakoon, D. M. N., Reardon, C. L., Paulitz, T. C., Izzo, A. D. and Mazzola, M. 2012. Long-term suppression of Pythium abappressorium induced by Brassica juncea seed meal amendment is biologically mediated. Soil Biology and Biochemistry 51: 44-52. <br /> <br /> Weller DM, Mavrodi DV, van Pelt JA, Pieterse CMJ, van Loon LC, and Bakker PAHM 2012. Induced systemic resistance in Arabidopsis thaliana against Pseudomonas syringae pv. tomato by 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens. Phytopathology 102: 403-412 <br /> <br /> Weller DM, Paulitz TC, Mavrodi DV, Mavrodi OV, Parejko JA, and Thomashow LS. Changing management practices and the environment: Impact on soilborne pathogens and biological control. pp 3-9 In: I Pertot, Y Elad, C Gessler, and A Cini (eds). Biological Control of Fungal and Bacterial Plant Pathogens. IOBC/WPRS Bulletin, Vol 78, Graz, Austria, 2012<br /> <br /> Wen, L., G. L. Hartman, and D. M. Eastburn. 2012. Suppression of soybean diseases through the use of cover crops. Phytopathology 102:S4.134. (abstract)<br /> <br /> Westphal, A., A. Pyrowolakis, R.A. Sikora, and J.O. Becker 2011. Occurrence of soil suppressiveness against Heterodera schachtii in California cropping areas. Nematropica 41:161-171.<br /> <br /> Witte, H., A. Ploeg, S. Subbotin, I. DeLey, J. Smith Becker, and J.O. Becker 2011. Observations on a root-knot nematode in Coachella Valley turf. J. Nematology 43: 294. (abstract)<br /> <br /> Wong, M-Y and Smart, C.D. 2012. A new application using a chromogenic assay in a plant pathogen DNA macroarray detection system. Plant Disease 96: 1365-1371.<br /> <br /> Yang, J., S. Benecke, D.R. Jeske, F. Rocha, J. Smith-Becker, P. Timper, J.O. Becker, and J. Borneman 2012. Population dynamics of Dactylella oviparasitica and Heterodera schachtii: toward a decision model for sugar beet planting. Journal of Nematology 44:237-244.<br /> <br /> Yang, JI, Loffredo, A., Borneman, J, Becker, JO. 2012. Biocontrol efficacy among strains of Pochonia chlamydosporia obtained from a root-knot nematode suppressive soil. Journal of Nematology 44:6771. <br /> <br /> Yang, Jiue-in, Paul M. Ruegger, Michael V. McKenry, J. Ole Becker and James Borneman. 2012. Correlations between root-associated microorganisms and peach replant disease symptoms in a California soil. PLoS One 7:e46420.<br /> <br /> <br /> <b>Extension and Technical Publications</b><br /> <br /> Abawi, G. S. and K. Moktan. 2012. Improve crop yield and get on your fields quicker with good soil management. Empire State Fruit and Vegetable Expo, Syracuse, NY. Proceedings, 3 pp. <br /> <br /> Abawi, G. S. and K. Moktan. 2012. Vegetable disease control and the impact of soil health management practices. Empire State Fruit and Vegetable Expo, Syracuse, NY. Proceedings, 3 pp.<br /> <br /> Abawi, G. S., C. Petzoldt, and K. Moktan. 2012. Practical ways to assess and manage soil health for disease control and improved yield. Great Lakes Expo, MSU Extension Proceedings, 3 pp, December 4  6, 2012; Grand Rapid, MI.<br /> <br /> Becker, J.O. 2010. Carrot Seed Treated with Nematicides: A New Plant Protection Tool? Carrot County 18 (1):8-9.<br /> <br /> Becker, J.O., A. Ploeg, and J. Nunez 2012. Evaluation of novel nematicides for management of root-knot nematodes. California Tomato Research Institute - 2011 Annual Report 105-110.<br /> <br /> Becker, J.O., and A. Ploeg 2012. Evaluation of novel nematicides to mitigate root-knot nematode damage in carrot production. CA Fresh Carrot Advisory Board Annual Report 2011, pp. 7-14.<br /> Dick, M. and Parke, J. 2012. Phytophthora kernoviae. Forest Phythophthoras 2: (in press)<br /> Dunn, A.R. and Smart, C.D. 2012. Fungicide resistance found in Phytophthora blight isolates from Western New York. Veg Edge newsletter April 2012.<br /> <br /> Dunn, A.R., Smart, C.D., Reiners, S. and Mazoruek, M. 2012. Comparing yield and disease incidence among Phytophthora tolerant sweet peppers. Proceedings of the 2012 New York Fruit and Vegetable Expo, Syracuse, NY. On-line at http://www.hort.cornell.edu/expo/proceedings.php<br /> <br /> Griesbach, J.A., Parke, J. L., Chastagner, G.C., Grunwald, N.J., Aguirre, J. 2012. (2nd ed.) Safe procurement and production manual: a systems approach for the production of healthy nursery stock. 105 pp. Oregon Association of Nurseries, Wilsonville, OR. http://oan.org/associations/4440/files/pdf/SafeProduction.pdf <br /> <br /> Hulbert, S., Guy, S., Pan, W., Paulitz, T. Schillinger, W. and Sowers, K. 2012. Camelina Production in the Dryland Pacific Northwest. Washington State University Extension Publication. FS073E. June, 2012.<br /> <br /> Jones, L.A., Worobo, R. and Smart, C.D. 2012. Testing for pathogens in irrigation water. Proceedings of the Mid-Atlantic Fruit and Vegetable Convention.<br /> <br /> Koening, R., Paulitz, T.C., Schroeder, K.L., Carter, A., Pumphrey, M., Huggins, D. and Campbell, K. 2011. Soil acidity and aluminum toxicity in the Palouse region of the Pacific Northwest. Washington State University Extension Publication. FS050E. October, 2011.<br /> <br /> Lange, H.W., Smart, C.D., and Seaman, A.J. 2012. Evaluation of fungicides allowed for organic production on powdery mildew of zucchini, 2011. Plant Disease Management Reports (online) Report 6:V104.DOI:10.1094/PDMR06<br /> <br /> Lange, H.W., Smart, C.D., and Seaman, A.J. 2012. Evaluation of fungicides allowed for organic production on downy mildew of cucumber, 2011. Plant Disease Management Reports (online) Report 6:V103.DOI:10.1094/PDMR06. <br /> <br /> Lange, H.W., Smart, C.D., and Seaman, A.J. 2012. Evaluation of fungicides allowed for organic production on foliar diseases of tomato, 2011. Plant Disease Management Reports (online) Report 6:V105.DOI:10.1094/PDMR06. <br /> <br /> Lange, H.W. and Smart, C.D. 2012. Evaluation of plant defense activators and bactericides for the control of black rot on cabbage, 2011. Plant Disease Management Reports (online) Report 6:V106.DOI:10.1094/PDMR06<br /> <br /> Okubara P, Schroeder K, Paulitz, T, Chen W 2012. What lurks beneath, unraveling the mysteries of Rhizoctonia and Pythium. Wheat Life, November issue.<br /> <br /> Okubara PA, Yan G, Smiley RW 2012. Molecular Diagnostics for Plant-Parasitic Nematodes in the Pacific Northwest. 2012 Dryland Field Day Abstracts, Technical Report 12-1, p. 34.<br /> <br /> Parke, J. and Fisher, P. 2012. Treating irrigation water to eliminate water molds. Pages 5-47 through 5-49 in: Pacific Northwest Plant Disease Management Handbook (J. W. Pscheidt and C. M. Ocamb, eds.) A Pacific Northwest Extension Publication (Oregon State University, Washington State University, and University of Idaho). Online at: http://pnwhandbooks.org/plantdisease/pesticide-articles/treating-irrigation-water-eliminate-water-molds<br /> <br /> Paulitz, T. C., Elling, A., Garland-Campbell, K. and Smiley, R. 2012. Rooting out the problems: Unseen nematodes take a visible bite out of profits. Wheat Life: July, 2012.<br /> <br /> Ploeg, A., O. Becker, and J. Nunez 2010. Use of cruciferous cover crops and seed coating to manage root-knot nematode in carrot. 2009 California Fresh Carrot Advisory Board Annual Report. pp. 71-78.<br /> <br /> Ploeg, A., O. Becker, and J. Nunez 2011. Use of cruciferous cover crops and seed coating to manage root-knot nematode in carrot. 2010 California Fresh Carrot Advisory Board Annual Report. pp. 93-99.<br /> <br /> Ploeg, A., O. Becker, and J. Nunez 2012. Use of mustard seed meal and carrot seed coating to manage root-knot nematodes in carrot. 2011 Annual Report California Fresh Carrot Advisory Board. pp. 47-51.<br /> <br /> Smart, C.D. and Hansen, Z. 2012. 2012 Trial of late blight resistance in tomato varieties. Veg Edge newsletter November 2012  reprinted in other newsletters.<br /> <br /> Smart, C.D. 2012. Cultivating cole crops; Diseases of cole crops. Handout for Cultivating Cole Crops Workshop, and reprinted in newsletters (March 2012)<br /> <br /> Smiley, R., Marshall, J. and Paulitz, T. 2012. Cereal Cyst Nematode Tolerance and Resistance in Spring Wheat. Grower publication- Oct. 9, 2012<br /> <br /> Smiley, R., Paulitz, T. C. and Marshall, J. 2012. Controlling Root and Crown Diseases of Small Grain Cereals. Extension Bulletin PNW 639. <br /> <br /> <br /> <br /> <b>Extension and Outreach Presentations</b><br /> <br /> <br /> Becker, J.O. Vegetable crop update meeting, UC West Side Research and Extension Center, Five Points, December 4, 2012. "Root-knot disease on vegetables and their causal agents." (invited hands-on demonstrations).<br /> <br /> Becker, J. O. Vegetable crop update meeting, UC West Side Research and Extension Center, Five Points, December 4, 2012. "Biological, biorational and conventional nematicides: New tools for management of plant parasitic nematodes?" (invited presentation)<br /> <br /> Becker, J. O. California Association of Pest Control Advisers Ventura Entomology Meeting, Santa Paula, CA, November 14, 2012. "New leads in plant parasitic nematode management and disease control". (invited presentation)<br /> <br /> Becker, J. O .California Association of Pest Control Advisers Ventura Entomology Meeting, Santa Paula, CA, November 14, 2012. "Root-knot nematodes and their disease symptoms on various crops." (invited "show & tell" presentation)<br /> <br /> Ploeg, A and Becker, J. O. Agrochemical Industry Nematology Training Session, UC South Coast Research and Extension Center, Irvine, CA, Oct. 24, 2012. "Research techniques for Greenhouse and Field Evaluations of Biological and Chemical Tools against Plant Parasitic Nematodes." (workshop with A. Ploeg)<br /> <br /> Becker, J. O. Progressive Farmers Meeting/University of California Cooperative Extension, Blythe, CA, Oct. 18, 2012. "New tools for the management of plant parasitic nematodes." (invited presentation)<br /> <br /> Becker, J. O. Botany & Plant Sciences Seminar BPS250 F2012, UC Riverside, October 17, 2012. Soils suppressive to plant parasitic nematodes (invited presentation)<br /> <br /> Becker, J. O. Environmental Horticulture Meeting, Irvine, CA, Oct 3-4, 2012. "A root-knot nematode in Coachella turf: A wimpy pathogen?" (presentation)<br /> <br /> Becker, J. O. Statewide CA Nematology Workgroup, Huntington Gardens, San Marino, CA, March 20. "Update on current research and outreach activities." (presentation)<br /> <br /> Becker, J. O. Soilborne Pathogens Conference/CA Nematology Workshop, Huntington Gardens, March 20-22. "Novel nematicides in processing tomatoes." (presentation)<br /> <br /> Becker, J. O. and Ploeg, A. Carrot Production Research Meeting, Bakersfield, March 8, 2012. "Evaluation of new nematicides in carrot production." (invited presentation)<br /> <br /> Becker, J. O. Pesticide Applicators Professional Association Seminar, El Centro, February 16, 2012. "Root-knot nematodes in carrot production: Evaluation of novel IPM strategies." (invited presentation)<br /> <br /> Becker, J. O. California Sugar Beet Industry Research Meeting, Holtville, CA, January 10, 2012. "Novel chemical, biorational and biological tools for plant parasitic nematode management." (invited presentation)<br /> <br /> Becker, J. O. Turfgrass and Landscape Institute, Etiwanda Gardens, Rancho Cucamonga, CA, December 14, 2011. "Soil Amendments for Managing Plant Parasitic Nematodes: Theory and Practice." (invited presentation)<br /> <br /> Escobar, C., and Hao, J. 2012. Assessing biological control agents and their fungicide sensitivities for potential integrated management of Sclerotinia stem rot in soybean. Wooster, OH, Jun. 13-14.<br /> <br /> Hao, J. 2012. Report to Midwest Nut Producers Council Annual Meeting. Clarksville, <br /> MI. Feb. 25.<br /> <br /> Hao, J. 2012 Antimicrobial activity in chestnut tissues corresponding with flavonol glycoside and terpenoid substances. 5th International Chestnut Symposium, National Conservation Training Center, Shepherdstown, WV. Sep. 6, 2012.<br /> <br /> Hao, J. 2012 Management of soilborne plant diseases. Beijing Plant Protection Station, Beijing, China, Jun. 5<br /> <br /> Hao, J. 2012 Report to Michigan Potato Industry Commission Field Day. Montcalm, MI. Aug. 9.<br /> <br /> Hao, J. 2012 Soil microbial community and soilborne diseases. China Agricultural University, Beijing, China, May 31.<br /> <br /> Hao, J. 2012. Annual report to USDA W-2147 program (Managing Plant Microbe Interactions in Soil to Promote Sustainable Agriculture). Riverside, CA. Dec. 6.<br /> <br /> Hao, J. 2012. Annual research report to Michigan Potato Industry Commission. East Lansing, MI. Jan. 12.<br /> <br /> Hao, J. 2012. Annual research report to Michigan Soybean Promotion Committee. East Lansing, MI. Jan. 25.<br /> <br /> Hao, J. 2012. Biological control agent BAC03 on controlling potato common scab. Nanjing Agricultural University, Nanjing, China, May 28.<br /> <br /> Hao, J. 2012. Microbial community in soil suppressive to potato common scab. Chinese Academy of Institution and Quarantine, Beijing, China, Jun. 5<br /> <br /> Hao, J. 2012. Report to Michigan Soybean Promotion Committee Field Day. East Lansing, MI. Aug. 18.<br /> <br /> Hao, J. 2012. Soil microbial community analysis in soilborne disease management. Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China, Jun. 6. <br /> <br /> Hao, J. J., Donis-Gonzalez, I. R., Jiang, H. H., and Fulbright, D. W. 2012. Antimicrobial activity in chestnut tissues corresponding with flavonol glycoside and terpenoid substances. The 5th International Chestnut Symposium. Shepherdstown, WV. Sep. 4 to 8. <br /> <br /> <br /> Okubara PA, Mavrodi O, Maketon C, Walter N, Aly H, Taylor CG 2012. Pseudomonas-based approaches for suppression of soilborne pathogens and pests. 2nd ISBioPEN Symposium Proceedings, Bangkok, Thailand, September 24-25, 2012.<br /> <br /> Okubara, P. A. 2012. Wheat Root Defense Gene Induction by Biocontrol Pseudomonas fluorescens. American Phytopathological Society-Pacific Division, Sacramento, CA, June 29, 2012.<br /> <br /> Okubara, P. A. Molecular Strategies for Controlling Necrotrophic Soilborne Pathogens of Wheat. Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, May 22, 2012.<br /> <br /> Parke, J. A. Systems approach for management of nursery diseases and pests. NW Ag Show, Portland, OR. Jan. 26, 2012. 55 participants.<br /> <br /> Parke, J. Biology and treatment of water molds in recycled irrigation water. University of California Nursery and Floriculture Alliance. Nursery/Floriculture Disease Management Symposium. Oct. 25, 2012. Watsonville, CA. 100 participants. <br /> <br /> Parke. J. A. Systems approach for managing diseases of ornamentals: theory and practice. University of California Nursery and Floriculture Alliance. Nursery/Floriculture Disease Management Symposium. Oct. 25, 2012. Watsonville, CA. 100 participants. <br /> <br /> Paulitz, T. C. 2012. Management of Root Diseases of Wheat Under No-Till Agriculture in the Pacific Northwest Rhizoctonia: A Case Study. Department of Agriculture and Food Western Australia, Perth, WA Australia Nov. 27, 2012.<br /> <br /> Paulitz, T. C. 2012. Management of Root Diseases of Wheat Under No-Till Agriculture in the Pacific Northwest Rhizoctonia: A Case Study.. Nanjing Agriculture University and Huazhong Agriculture University in Wuhan, May 15-26.<br /> <br /> Paulitz, T. C. 2012. Canola Diseases Oilseed Crop Production Workshop, Colfax, WA. Jan. 26, 2012<br /> <br /> Paulitz, T. C. 2012. Management of Fresh Wheat Residue for Irrigated Winter Canola Production. Department of Ecology, Washington State, Ag Burning Task Force. Spokane, WA. Feb. 7, 2012. <br /> <br /> Paulitz, T. C. 2012. The Role of Microbial Communities in the Natural Suppression of Rhizoctonia Bare Patch of Wheat in the USA and Australia. The 7th Australasian Soilborne Diseases Symposium, Freemantle, WA, Sept. 17-20, 2012<br /> <br /> Paulitz, T. C. 2012. The Role of Microbial Communities in the Natural Suppression of Rhizoctonia Bare Patch of Wheat in the USA and Australia. CSIRO Floreat, Western Australia. Nov. 12, 2012<br /> <br /> Paulitz, T. C. 2012. The Role of Microbial Communities in the Natural Suppression of Rhizoctonia Bare Patch of Wheat in the USA and Australia. CSIRO Canberra. ACT Nov. 21, 2012<br /> <br /> Paulitz, T. C. 2012.The Role of Microbial Communities in the Natural Suppression of Rhizoctonia Bare Patch of Wheat in the USA and Australia. CSIRO Adelaide, South Australia Nov. 23, 2012.<br /> <br /> Paulitz, T. C. Soilborne Pathogens in Wheat- Rhizoctonia and Cereal Cyst Nematode. Jan. 27, 2012, Walla Walla Growers, Walla Walla, WA<br /> <br /> Paulitz, T.C. 2011. Nematodes: Symptoms and Management. Presented to the Asotin County Extension Grower Workshop, Clarkston, WA, Dec. 17, 2011.<br /> <br /> Paulitz, T.C. 2011. Soilborne Pathogens in Wheat- Fusarium, Rhizoctonia, and Cereal Cyst Nematode. Nez Perce County Grower Workshop, Lewiston, ID, Oct. 18, 2011. <br /> <br /> Paulitz, T.C. Root Disease Research at ARS Pullman-Whats New? Spokane Farm Forum, Ag Expo, Feb. 7, 2012<br /> <br /> Ploeg, A and Becker, J. O. Agrochemical Industry Nematology Training Session, UC South Coast Research and Extension Center, Irvine, CA, Oct. 24, 2012. "Research techniques for Greenhouse and Field Evaluations of Biological and Chemical Tools against Plant Parasitic Nematodes." (workshop with A. Ploeg)<br /> <br /> Rosenzweig, N., Lu, X. H., Jiang, H., and Hao, J. 2012. Multigene analysis of Pythium species causing carrot cavity spot in California and Michigan. APS Annual Meeting, Providence, RI, Aug. 4  8.<br /> <br /> Schroeder, K. Canola Diseases. Far West Ag. Conference Dec. 11, 2012. Pasco, WA.<br /> <br /> Schroeder, K. L. 2012. Rhizoctonia root rot of cereals: unraveling the disease complex. Commodity Classic, Nashville, TN. March 2, 2012.<br /> <br /> Stanghellini, M. 2012. Biology and management of soil-borne root-infecting pathogens. AGRADIS, San Diego, California. July 31, 2012. <br /> <br /> Stanghellini, M. 2012. Pythium brassicum: a novel family-specific root pathogen. <br /> Soil Fungus Conference, March 21, 2012 <br /> <br /> Stanghellini, M. 2012. Update on ecology and biology of Monosporascus cannonballus Strokan-Hanes-McCaslin Foundation, June 24, 2012, San Marcos, California. <br /> <br /> Weller, D. and Thomashow, L. 2012. Soil microbial changes with irrigation" WSU Lind Dryland Station Field Day, June, 14, 2012. <br /> <br /> Witte, H. and Becker, J.O. Turf & Landscape Field Day, Agricultural Operations, UC Riverside, September 13, 2012. "Update on studies concerning Coachella Valley rot-knot nematodes." (invited presentation)<br /> <br /> <br /> <br /> <b>Websites maintained<br><br /> Forest Phytophthoras of the World www.ForestPhytophthoras.org<br><br /> Online Phytophthora Course: Training for Nursery Growers http://oregonstate.edu/instruct/dce/phytophthora/index.html<p> <br /> <br /> Graduate student theses supervised</b><br /> <br /> <br /> Kandel, S. 2012. A survey of root lesion and cereal cyst nematodes in the dryland wheat production areas of Eastern Washington and resistance of Pacific Northwest wheat varieties. MSc thesis, Washington State University.<br /> <br /> Leytem, A. B. Response of Striga-susceptible and Striga-resistant sorghum genotypes to soil phosphorus and colonization by an arbuscular mycorrhizal fungus. M.S. thesis, Oregon State University. 84 pp.<br /> <br /> Shay, S. 2012. Viability and infective potential of Phytophthora pini zoospores in a recirculating irrigation system. M.S. thesis, Oregon State University. 85 pp.<br /> <br /> Stamm, E.A. 2012. The effects of Phytophthora ramorum stem inoculation on aspects of tanoak physiology and xylem function in saplings and seedlings. M.S. thesis, Oregon State University. 80 pp.<br />

Impact Statements

1. Demonstrated that the pump and spray components of certain irrigation systems can reduce the infectivity of <i>Phytophthora</i> zoospores, potentially resulting in less foliar disease on nursery plants irrigated with recycled water.
2. Showed that sorghum breeding lines resistant to <i>Striga</i> retain responsiveness to arbuscular mycorrhizal fungi and to P amendment of soils. Results are important for maintaining soil health for international agriculture.
3. Demonstrated that soil solarization in container nurseries can be effective in disinfesting soil contaminated by <i>Phytophthora</i> species, including the quarantine pathogen <i>P. ramorum</i>. This could be a low cost and low technology alternative to soil fumigation.
4. Identified minimum best management practices in nursery and greenhouse operations for controlling pests and pathogens using a systems approach. These BMPs will directly help growers and will contribute to the development of new national policies in our federal regulatory system that should be more effective than our current end-point inspection program in preventing disease and interstate movement of pest-infested nursery plants.
5. Will provide pepper producers and industry with information on the efficacy of soil treatment with bioactive crop residues on reducing soil inoculum potential of soilborne pathogens. This research also promotes the notion of using biorational products containing multiple microbial species as a sound ecological approach for control of soilborne pathogens. Additionally, a review on the current status of knowledge and research needs on <i>Phytophthora capsici</i>, an economically significant pathogen of many vegetable crops, was prepared for use by producers, crop consultants, industry, graduate and undergraduate students, K-12 teachers and other scientists.
6. Discovery of controlling mechanisms for antagonism factors (Obj. 2) may lead to the development of more field effective biocontrol agents. In addition to providing a new tool for disease management, use of such agents is compatible with other management practices and might result in reduced chemical fungicide inputs. Teaching activities provided critical training relating to biological pest control to the next generation of plant scientists and agriculturalists (Obj. 4).
7. The presence of the nematophagous <i>Dactylella oviparasitica</i> and similar fungi in many sugar beet production fields suggests the potential of developing suppressive conditions against the beet cyst nematode.
8. Seed coatings with Avicta provided significant protection against early season attack by root-knot nematodes in carrot field trials. Plant protection against root-knot nematodes was improved by combining Avicta with fungal or bacterial biocontrol agents.
9. If the results of the Illinois cover crops project verify that use of fall planted cover crops prior to planting soybeans results in the reduction of soybean diseases, then the use of cover crops in corn:soybean rotation systems could increase dramatically. This would, in turn, increase the overall diversity of the cropping system, reduce the need for chemical disease control strategies, reduce problems of soil erosion, and increase the overall sustainability of the production system.
10. We determined the relationships between the amounts of the fungus <i>Dactylella oviparasitica</i> and the plant-parasitic nematode <i>Heterodera schachtii</i>. We anticipate that monitoring both the <i>Dactylella oviparasitica</i> and <i>Heterodera schachtii</i> population levels will lead the development of a more effective predictive tool for making sugar beet planting decisions.
11. We identified a list of bacteria that correlated with peach replant disease symptoms. Identifying the causal agents of replant disease should facilitate the development of targeted agents to control them and of plants that are resistant to them.
12. <i>Coniothyrium minitans</i> was the most effective among the test biological control agents (BCAs) in reducing the disease and Cobra enhanced its efficacy. BCAs were insensitive to some chemicals in mycelial growth and spore germination on culture media amended with fungicides, herbicides and fertilizers, therefore can be applied by mixing with those chemicals.
13. In the greenhouse, BAC03 reduced potato common scab significantly, and promoted the tuber size of potato as well. Oregano essential oil, and horseradish significantly decreased the disease severity of potato common scab compared to non-treated control. BAC03 has multiple functions including disease suppression, plant growth promotion, and induced systemic resistance in plant. This product is expected to be commercialized for broader application.
14. Root diseases and soil health are major constraints to vegetable production and profitability in New York State and the NE region. It is known that the use of appropriate cover and rotational crops and in the right sequence as well as reduced tillage systems are a few options available for the sustainable management of soil health constraints. Cover and rotational crops and also tillage systems can have a major influence on the soil population and damage of numerous soilborne pathogens. Thus, results obtained from these studies will aid growers and other agricultural service providers in selecting the appropriate crops and other production practices needed to address the root health and soil health constraints impacting crop production. Successful management of root and soil health constraints will contribute to increasing farm profitability and environmental quality.
15. Identification of bacterial community associated with natural suppression of Rhizoctonia root rot of wheat in the field may lead to development of cultural tools to enhance this sustainable method of disease management.

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