W2186: Variability, Adaptation, and Management of Nematodes Impacting Crop Production and Trade

(Multistate Research Project)

Status: Inactive/Terminating

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SAES-422 Reports

Annual/Termination Reports:

[01/23/2009] [01/06/2010] [01/07/2011] [01/09/2012] [01/02/2013]

Date of Annual Report: 01/23/2009

Report Information

Annual Meeting Dates: 11/13/2008 - 11/14/2008
Period the Report Covers: 10/01/2007 - 09/01/2008

Participants

See meeting minutes.

Brief Summary of Minutes

Minutes Attachment:

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Accomplishments

W-2186: Variability, Adaptation, and Management of Nematodes Impacting Crop Production and Trade 2008 Annual Report NOTE: In order to highlight the challenges associated with finding and dealing with the potato cyst nematode and trade issues that recently have come to light, Oregon's report under Objectives 1 and 4 is presented first and separately. Oregon's Report: Objective 1: Characterize genetic and biological variation in nematodes relevant to crop production and trade. Golden potato cyst nematode (Globodera rostochiensis) was first detected in North America from New York in 1941 and later from Newfoundland in 1962 and British Columbia in 1965. Pale potato cyst nematode (G. pallida) was also reported from Newfoundland in 1968. Then in 2006, G. pallida was discovered in Idaho and G. rostochiensis was reported from Quebec. Samples from potato seed fields in Alberta were found to contain G. rostochiensis in 2007. Guidelines to protect the potato industries in both Canada and the United States from spread of potato cyst nematodes (PCN) were approved by APHIS and CFIA early in 2008. Oregon State University owns a farm in Central Oregon near Powell Butte where seed from all the potato breeders in the Tri-State (ID, OR, WA) Variety Development Program is increased for distribution to other areas for further evaluation. The farm is in an ideal location because it is isolated from other potato production areas, which minimizes the probability of introducing potato pests into early generation potato seed. Potato seed grown on this farm during 2007 was scheduled to be shipped to Canada in 2008 so the field was sampled on April 28, 2008 in accordance with the new U.S.-Canadian guidelines. When the Oregon Department of Agriculture (ODA) processed the samples, six nematode cysts were recovered and sent to the USDA Nematology Laboratory in Beltsville, MD. The cysts were identified as Globodera by morphological and molecular procedures but the species identification was inconclusive. The Oregon Department of Agriculture imposed an Administrative Directive on the farm to prevent any movement of potatoes or soil off the property. More soil was collected and processed on May 15 and an additional 18 cysts were found, eight of which were sent to Beltsville. These cysts were also identified as Globodera but were morphologically and molecularly distinct from criteria used by APHIS to identify G. pallida (pale cyst nematode) or G. rostochiensis (golden nematode) and thus, were not determined to be PCN. Therefore, ODA rescinded the Administrative Directive since no regulatory action was required. Impact Statement: Although the nematode was not identified as G. pallida or G. rostochiensis there is still interest and concern about what it is and how it may impact potato growth. Nothing about its host range and potential pathogenicity is known. While it could potentially be a parasite of native vegetation from the area, possibly reproducing on weeds in agricultural fields, it could also be a pathogen of potato, a new species of PCN. If it were a pathogen of potato, the level of pathogenicity would have to be established to determine if it warrants regulation. If it is not a pathogen of potato it may represent a potentially valuable model organism for studying aspects of biology and management of a nematode that may be biologically similar to PCN without the constrictions of working with a regulated pest species. Objective 4: Implement rapid information transfer of project results to stakeholders. Oregon is a major exporter (4.6 million lb in 2008) of grass seed to Korea. Several shipments of grass seed collectively worth over $200,000 were rejected by the Korean National Plant Quarantine Service (NPQS) due to the presence of nematodes and returned to Oregon. The primary grower/shipper that was impacted requested assistance from the Oregon State University Nematology program on how to manage the grass seed crop so that these rejections would not occur. The nematodes listed were Aphelenchoides haguei, Paraphelenchus acontioides and Subanguina sp. These nematodes were listed on the Korean Harmful Organism List and thus were not inspected for by the Oregon Department of Agriculture when issuing phytosanitary certificates required for export. Inspection of samples from grass seed that returned from Korea by an OSU nematologist detected Aphelenchoides and Paraphelenchus, but not Subanguina. Since the species of Subanguina was not determined by NPQS and since Subanguina was not recovered from samples returned to Oregon the relative risk associated with the inceptions of Subanguina by NPQS could not be determined. Some species are pathogenic but little is known about other species. However, detections of Subanguina by NPQS were only in red fescue and blends containing red fescue. The red fescue included in these shipments had been obtained from a source from outside of Oregon for the purpose of making these blends. The grower was advised to find a different supplier of red fescue for blending with his seed. Research of the literature on A. haguei and P. acontioides revealed that both nematodes fed on fungi and that neither was reported as a plant pathogen. Therefore, neither species presented any risk to Korean agriculture. A letter documenting the biology and degree of risk from A. haguei, P. acontioides and Subanguina sp. was sent to APHIS where it was forwarded onto NPQS. Subsequently, NPQS replied to APHIS that A. haguei, and P. acontioides would no longer be regulated at the port of entry. However, ruling on the risk assessment of Subanguina was delayed until the species could be determined. Both APHIS and NPQS were very helpful and accommodating in resolving this issue. Impact statement: Rejections of Oregon grass seed exported to Korea due to inceptions of nematodes associated with the seed were resolved when it was determined that the nematodes in questions did not pose a risk of plant disease to Korean Agriculture. Annual value of the contract of the impacted stakeholders alone was $2 million. Had these nematodes been found in seed from other farms in Oregon, exports of $5 million (2007) could have been in jeopardy. All States' Report: Objective 1: Characterize genetic and biological variation in nematodes relevant to crop production and trade. Root-knot nematode (Meloidogyne spp.) interactions with resistance genes in the host crops cowpea (Vigna unguiculata), lima bean (Phaseolus lunatus), and cotton (Gossypium spp.) were examined to determine specificity of nematode responses to different resistance genes in these crop plants in CA. These studies are coupled with efforts to breed new varieties with improved nematode resistance. New resistance sources have been identified in each of these crop species that confer unique specificities that match avirulence genes in the nematode. An analysis of the resistance inheritance in Lima bean Cariblanco N and its donor L-136 was completed. In crosses between the resistant parent and susceptible Henderson Bush, a series of three independent resistance genes was determined to control resistance. One gene was found to confer root galling resistance to M. incognita, a second gene conferred resistance to M. incognita reproduction, and a third gene conferred resistance to M. javanica root galling. Tests with recombinant inbred lines from the cross confirmed that each gene acted alone, and that a combination of all three genes was necessary to provide comprehensive nematode resistance. The independence of galling and reproduction resistance traits provides an excellent model system for dissecting molecular pathways governing these important plantnematode interactions. In cowpea, additional field isolates of both M. incognita and M. javanica were found in California cowpea fields that were virulent to gene Rk. In cotton, genetic analysis, molecular mapping, and marker development revealed a major M. incognita resistance gene, rkn1, on chromosome 11 in the upland cotton (Gossypium hirsutum) Acala NemX. In progenies derived from crosses between Acala Nemx and the root-knot susceptible G. barbadense cultivar Pima S7, a significant number of individual plants were found with extremely high levels of resistance. These transgressive segregants were much more resistant than the resistant parent of the cross. Genetic and molecular marker analysis using BAC-end derived and other SSR markers revealed a gene in Pima S7, named RKN2, that when combined with rkn1 from Nemx, resulted in the ultra-resistant phenotype. Genetic mapping of the markers revealed that gene RKN2 is also located on cotton chromosome 11, in the same region as rkn1. The novel resistance based on these clustered genes has important potential for improving nematode management in cotton. The SSR markers tightly linked to each gene were confirmed to be effective for indirect screening of the high resistance in a marker-assisted selection approach to cotton breeding. The RKN2 gene markers were used to screen cottons with different genome origins, and indicated that RKN2 originated from the A2 cotton genome. In Hawaii, evaluation of semi-wild Ethiopian (ET) coffee (Coffea arabica) for resistance to the root-knot nematode, M. konaensis, showed that ET25B and ET15 grew well in the presence of nematodes and may be of use in the coffee breeding program. Evaluation of taro (Colocasia esculenta) germplasm for resistance and tolerance to M. javanica found differences that while statistically different would not provide sufficient levels of control. In Idaho, screening of onion cultivars to P. penetrans indicated that Caveat, Vision, R10 Tinto, and Mercury were resistant to P. penetrans. 'Caveat' was considered to have the best resistance to P. penetrans which would be useful for nematode management. Cultivars susceptible to P. penetrans included Sanfan and Sweet Sunrise. An experiment was conducted under green house conditions to evaluate the tolerance level of ten alfalfa genotypes to the Columbia rot knot nematode M. chitwoodi. In the variety Ts 5011 there was a significant increase in the fresh and dry weight of shoot and root followed by the lowest level of M. chitwoodi population in the root. Screening of sugar beet accessions to sugar beet cyst nematode indicated that the lowest number of cysts on the root was observed in the sugar beet accession PI 540574. To determine whether PI 88788 resistance was changing or whether soybean cyst nematode (Heterodera glycines) was adapting to this source of plant resistance was investigated in TN as part of a regional peoject. This source of resistance is present in approximately 97% of commercial seed. Tennessee represented the state which had deployed plant resistance to soybean cyst for over 30 years. Soil samples were collected throughout the state and egg population density was increased until there were sufficient eggs to characterize the population. More than 4,000 soil samples were collected but only 40 had sufficient population density to characterize. No HG Type 0 was detected and all populations were able to reproduce on PI 88788. In Hawaii, a new infestation of the soybean cyst nematode on Kauai, and a population of M. javanica that has proven to be devastating on grapefruit (Citrus × paradisi) but limited in geographic area, were discovered. In MI, analysis of three, from mineral soils, and one from muck soil, populations of M. hapla on seven carrot cultivars adapted to the Great Lakes Region and 'Rutgers' tomato (susceptible control) was investigated. While varying in their degree of susceptibility, all carrot cultivars were equal to or more susceptible than tomato. Across nematodes and experiments, the population from muck soil infected the least and a population from sandy soil infected the most. The results support the hypothesis that soil-driven conditions may influence parasitic variability of M. hapla populations. In collaboration with principle investigators from University of Florida and co-investigators from the University of New Hampshire, researchers at the University of Nebraska, Lincoln, have been examining the application of metagenomic soil analyses for the assessment of nematode community species composition. Their focus has been on the suitability of different primer sets to best represent DNA diversity from nematodes extracted and collectively homogenized for PCR amplification. Comparisons between metagenomic estimates of diversity and estimates derived from a sequential analysis of individual nematodes indicate that the metagenomic approach recovers virtually all the diversity found in the sequential analysis. Such approaches will be helpful as integrating nematode community structure into various aspects of nematode management strategies increase (see Objective 3). Objective 2: Determine nematode adaptation processes to hosts, agro-ecosystems and environments. In NM, populations of yellow nutsedge (Cyperus esculentus) were collected from different geographic regions of North America, including areas outside the geographic range of M. incognita, and are being propagated in the greenhouse. Studies are planned to determine if interactions that have been observed in the southwestern USA, such as host suitability for nematode reproduction or proliferation of nutsedge tuber production following nematode infection, represent local co-adaptation of the nematode and weed, or are inherent within yellow nutsedge. In 2007, areas of high M. incognita infestation were identified in heavy-textured, clay loam soils in chile pepper fields in Doña Ana and Luna counties that are poorly suited to the nematode. Chile infection appeared to be limited to areas with high incidence of annual weeds that were also infected by M. incognita and Verticillium dahlia. We hypothesize that pockets of difficult-to-control annual weeds may act as host reservoirs for the nematode under these conditions. In 2008 a greenhouse experiment was conducted to determine the host suitability of chile pepper, spurred anoda (Anoda cristata), tall morningglory (Ipomea purpurea), and Wrights groundcherry (Physalis wrightii) to M. incognita and V. dahlia. Data are still being collected, after which statistical analysis will test the following questions relative to the plant responses: 1) what is the response of each plant species to the nematode and fungal pathogen (alone and in combination)? 2) What is the relative sensitivity of the four plant species to the nematode, fungus, and the combination (data will be expressed as a % of the uninoculated control for this analysis)? In 2008 additional chile pepper fields in southeastern NM were found to be infested with M. hapla. Past surveys comprised of 10% each of the cotton, chile, and alfalfa hectarages revealed primarily M. incognita in this region. Future work is planned to determine the frequency of single versus mixed-species root-knot populations throughout the region and to identify factors that may be contributing to proliferation of M. hapla. In TN, over 300 soil samples were examined for the presence of the goose grass cyst nematode found parasitizing corn in 2006. The nematode can consistently be recovered from the field site detected in 2006 and several other field sites continue to test positive in greenhouse bioassays. The exact location of the original find in 1978 is still not known. Host studies indicate that only goosegrass, corn and close relatives are hosts. No field crops typical of the Midwest are hosts nor are common cyst nematode hosts such as potato, tobacco, or soybean. In Idaho, pathogenicity studies of Pratylenchus penetrans on onion indicated that this nematode caused significant plant growth reduction at the lowest inoculum level of two nematodes/ cm3 soil. Yield loss of onion increased significantly at all inoculum level. The same quadratic decrease and increase trend in plant and nematode parameters were observed in onions inoculated with the root knot nematode M, hapla. Significant plant growth reduction by M. hapla started at the density of two J2/ cm3 soil. Bulb weight was reduced by 17.5% to 41.3% with the increasing inoculum levels in field microplots. More damage was caused by P. penetrans than M. hapla when the two species were inoculated at the same density. There was a competition between P. penetrans and M. hapla on onion. Significantly more damage in onion was observed when the two species were inoculated simultaneously at a 1:1 ratio rather than either species alone. P. penetrans and M. hapla suppressed each other for multiplication on onion. Nematode population in roots and the final total population at harvest were reduced for both species when they existed together in soil, but the suppressive effect of P. penetrans on M. hapla was more severe than that of M. hapla on P. penetrans. In MI, exploiting the multi-purpose traits of brassicas was investigated by testing the effects of 0 (check), 4,000 or 8,000 NRKN eggs/300 cm3 of either sandy, sandy loam, or muck soil on arugula's (Eruca sativa L., cv 'Roquette') ability to trap an M. hapla population and if nematode infection affects biomass accumulation and vegetative (nutritional) quality. Roquette was selected to meet organic production requirements. Similar numbers of nematodes were recovered from the high and low nematode treatments in the three soil types and nematode infection had no effect on plant growth or nutritional quality of arugula. However, arugula's growth and leaf nutritional quantity were significantly affected by soil type. In addition to providing basis for entrepreneurial opportunities to test arugula's trap, vegetable, and possibly biofumigant attributes from one seeding, the results support the hypothesis that arugula can trap M. hapla in different soil types without affecting its vegetative growth and quality. Objective 3: Develop and assess nematode management strategies in agricultural production systems. Developing and integrating ecologically friendly nematode management alternatives has been as complex as the croppings systems diversity. The Columbia root-knot nematode, M. chitwoodi is the most important root-knot nematode pathogen of potato, Solanum tuberosum, followed by the root-lesion nematode, Pratylenchus penetrans, and the stubby root nematode, Paratrichodorus allius. In addition, the Potato Cyst nematode (PCN), Globodera pallida, found in Idaho in 2006, is a new threat to the WA potato industry. Furthermore, G. rostochiensis, a close relative to G. pallida has been found in Alberta, Canada, potato seed source for WA growers for several years. In order to deal with current and potentially emerging nematode problems, a variety of management options are being employed in vegetable and field crops. The use of organism-derived biofumigants like Muscodor albus, fungal endophyte, have been shown to be effective against multiple nematode species in tomato, pepper, bean and potatoes. Plant-derived biofumugants like brassicas show promising effects on plant-parasites without adversely affecting beneficial nematodes. As part of wPCN eradication plan, greenhouse assay using green manure is in progress. In Hawaii, growers have observed green manure crops growing in the field and are able to make better informed management decisions. In Idaho, a micro plot study using the new product (DMDS) on tomato at different rates for control of Columbia root-knot nematode indicated that all treatments significantly reduced the nematode population in comparison to the untreated control. A field experiment to study the efficacy of biopesticide at different rates for control of Columbia root-knot nematode in a potato field indicated that the percent of tubers with nematode infection in treated plots ranged from 31.5 to 97.8. Lowest level of nematode infection was recorded in the plots treated with Temik + Vydate treatment followed by the highest rates of WD and Chancellor treatments. Another field experiment with DMDS (ten treatments) indicated that nematode infected tubers as well as percent of nematode infection were significantly reduced by the treatments compared to control plots. Percent of tubers with nematode infection in DMDS treated plots ranged from 0.2 to 25.6. In WA, a comparison of naturally derived biofumigants and synthetic fumigants (double bio/synthetic fumigation) can protect potato tubers against M. chitwoodi. In order to manage foliar pest like Colorado potato beetle (Leptinotarsa decemlineata) and root-knot nematodes, augmentation and conservation of insect-attacking nematodes and fungi were tested in potatoes. Biofumigation interfered with augmented biocontrol in the soil and reduced some species of non-target organisms. A notable component of dealing with nematode-virus interactions in WA potato production has been the development of rapid detection of viruliferous nematodes, which, in return, allows growers to make judicious decisions on stubby root nematode control and appropriate farming practices. Integrating nematode community structure into agricultural nematode management is continuing in several fronts. In NM, data pertaining to nematode community structure (NCS), indicator of soil biological and agro-ecological changes, have been collected from soil samples from all surveys and nematode management experiments since 2006. At the request of local producers who are concerned about long-term irrigation commitments associated with 3-year alfalfa rotations used for suppression of the M. incognita/yellow nutsedge/purple nutsedge pest complex, experiments will be initiated in spring 2009 to evaluate the effectiveness of annual cover and rotation crops toward these ends. In TN, studies are continuing on effect of tillage on soybean cyst nematode reproduction and also on the effect of poultry litter on soybean cyst nematode reproduction. In both studies data are being collected on soil community analysis and normalized difference vegetative index (NDVI, physiological indicator of plant health) in addition to egg population density and yield. The objective is to explain the differences in reproduction seen with the different treatments. Among other things, accounting for and explaining agro-ecological health and complexities, for which NCS is an excellent indicator, are critical when imposing nematode parasitic variability management strategies. Expanding on the fertilizer use efficiency (FUE) model (which separates nutrient deficiency and toxicity from nematode parasitism as well as suitability of treatments designed to achieve desired biological and physio-chemical soil health conditions) and incorporating NCS, the MI group has developed cross-disciplinary models for testing soil amendment-driven management of biotic and abiotic factors. Objective 4: Implement rapid information transfer of project results to stakeholders. In addition to the list of four categories of publications, following are venues and avenues where research results were delivered to stakeholders: OR: - Update on cyst nematodes in potato. Hermiston Agriculture Research and Extension Center Potato Field Day. June, 2008. - Timing of in-season soil sampling for Columbia root-knot nematode. Hermiston Agriculture Research and Extension Center Potato Field Day. June, 2008. - Nematode management with crop rotation: Impact of biofuel crops. 34th Annual Hermiston Farm Fair and Trade Show, Hermiston, OR. November, 2007. NM: - The NM Vine and Wine Society (29 Feb - 1 March 2008). - The NM Chile Association advisory board (10 June 2008). - The NM Chile Association Chile Field Day (19 August 2008). - NM Certified Applicator Continuing Education Training (9 October 2008). HI: - Reports, letters, phone conversations, and theses. - Field days were held on several occasions to interact with taro growers. TN: - Soybean plant reaction to soybean cyst nematode for commercially available cultivars is published in the following websites. http://www.utextension.utk.edu/fieldCrops/soybean/diseases/disease_images/2007-Soybean-Report.pdf and http://www.utextension.utk.edu/fieldCrops/soybean/soybean_images/Soybean%20Variety%20Performance%20Tests%20in%20Tennessee%202007%20-%20for%20Web%20Posts.pdf WA: - Nematology Extension: http://www.prosser.wsUniversityedu/faculty/riga/Riga-index.html

Publications

Publications Attachment:

Attachment

Impact Statements

Natural host plant resistance genes are valuable in crop plants as effective and safe approaches to managing root-knot nematodes. Studies on their specificity, efficacy, and use in cropping systems advance their utilization in agriculture. New combinations of resistance genes hold promise for developing crop varieties with stronger and broader nematode resistance.
Identifying sources of resistance to root-knot nematodes in taro and coffee can be of direct use to growers as well as to breeders for incorporating the traits into desirable taro cultivars.
Developing transgenic coffee plants may offer growers alternatives for the management of root-knot nematodes that is sustainable and environmentally friendly.
Identifying infestations of soybean cyst nematode in HI will help state and federal regulators to better able to do their jobs.
Nematode competition analysis is helpful to understanding nematode adaptation in a given niche as well as to developing resistant cultivars.
Incorporating soil ecology and nematode parasitic variability will provide growers with new and integrated information that they can use when selecting cultivars.
Biological and plant-derived biofumigants will lead to developing sustainable management strategies.
Incorporating nematode community structure to nematode management strategies is critical to soil health management. The fertilizer use efficiency model and its modifications provide a foundation for agro-biologically and ecologically integrated and sustainable approaches to changing soil conditions.

Date of Annual Report: 01/06/2010

Report Information

Annual Meeting Dates: 11/06/2009 - 11/07/2009
Period the Report Covers: 10/01/2008 - 09/01/2009

Participants

E. Caswell-Chen, University of California Davis;
P. Donald, USDA ARS Tennessee;
A. Elling, Washington State University;
R. Ingham, Oregon State University;
H. Melakelabrahan, Michigan State University;
T. Powers, Nebraska State University;
R. Robbins, University of Arkansas;
P. Roberts, University of California Riverside;
B. Sipes, University of Hawaii;
S. Thomas, New Mexico State University;
I. Zasada, USDA ARS Oregon;

Guests:;
S. Chen, University of Minnesota;
G. Lawrence, Mississippi State University;
K. Lawrence. Auburn University

Brief Summary of Minutes

Minutes Attachment:

Attachment

Accomplishments

The project has four objects. Project activities are diverse and cover a wide range of agroecosystems. Project activities involve research spanning from basic molecular research into nematode genetics to applied control in cooperative field tests. Our accomplishments will be organized and reported under each of the four project objectives. Characterization of Nematode Genetic and Biological Variation Relevant to Crop Production and Trade A range of crops and plant-parasitic nematodes important in the western region were evaluated by project members. Recently developed soybean cultivars and breeding lines were evaluated for resistance to the soybean cyst nematode, the reniform nematode. Several lines and cultivars show promise with resistance equal to or greater than that currently deployed. Cotton has also been evaluated against reniform nematode and root-knot nematodes. Root-knot nematode (Meloidogyne spp.) interactions with resistance genes in the host crops cowpea (Vigna unguiculata), Lima bean (Phaseolus lunatus), and cotton (Gossypium spp.) were examined to determine specificity of nematode responses to different resistance genes in these crop plants. These studies are coupled with efforts to breed new varieties with improved nematode resistance. New resistance sources have been identified in each of these crop species that confer unique specificities that match avirulence genes in the nematode. Field screens of multiple advanced Lima bean breeding lines were conducted in fields infested with M. incognita and M. javanica. Several lines were found to be resistant to either one or both nematodes, and seed was collected for further advancement. The previous findings of at least three independent genes conferring resistance in the Lima pedigrees was supported by these field selection screenings. In cowpea, a consensus genetic map was developed based on six individual maps using six recombinant inbred line (RIL) populations. The high density map has more than 1000 EST-derived SNP markers covering the 11 linkage groups and spanning 680 cM at an average marker distance of 0.73 cM. Screening of three RIL populations segregating for the suite of Rk genes conferring M. incognita and M. javanica resistance was done in field and seedling growth pouch tests. The resistance phenotype data were used with the SNP markers for QTL mapping. Three main resistance QTL were identified on different linkage groups. The markers are gene-expression based and provide an entryway to fine mapping and isolation of the resistance genes, in conjunction with a newly constructed cowpea physical map whose BAC contigs have been SNP genotyped. The markers for the root-knot nematode resistance loci will facilitate marker-assisted breeding for nematode resistance using SNP-based high-throughput genotyping. In cotton, genetic analysis, molecular mapping, and marker development revealed a major M. incognita resistance gene, rkn1, on chromosome 11 in the upland cotton (Gossypium hirsutum) Acala NemX. In progenies derived from crosses between Acala NemX and the root-knot susceptible G. barbadense cultivar Pima S7, a significant number of individual plants were found with extremely high levels of resistance. These transgressive segregants were much more resistant than the resistant parent of the cross. Genetic and molecular marker analysis using BAC-end derived and other SSR markers revealed a gene in Pima S7, named RKN2, that when combined with rkn1 from NemX, resulted in the ultra-resistant phenotype. Genetic mapping of the markers revealed that gene RKN2 is also located on cotton chromosome 11, in the same region as rkn1. The novel resistance based on these clustered genes has important potential for improving nematode management in cotton. We continued gene action analysis by inheritance and QTL mapping and determined in both intraspecific and interspecific cotton crosses that a combination of allelic interaction, epistasis and heterosis operated in these crosses, with both additive and dominance effects revealed. These studies also refined the SSR markers, which can be used for marker assisted selection for resistance. Papaya (Carica papaya L.) trees infected with root-knot nematodes (Meloidogyne javanica) can be stunted, have lower yields, and increased sensitivity to stresses. The nematode reproduced on papaya cultivars Kapoho, Maradol, Saipan, Sunrise and Vietnam, and breeding lines UH Line D Poamoho, Richter 181.OM20-1, Richter 192.OM3-1, and Richter 192.OM3-2. In one test Saipan supported the least nematode reproduction (Rf = 0.6) whereas Richter 181.OM20-1 and Sunrise had the greatest Rfs (8.9 and 14.0 respectively). In a repeat of the test, nematode reproduction was greater on all genotypes, but the test was confounded by early plant death. The relation between nematode Pi and damage was quantified in Sunrise papaya. Sunrise root and shoot weight decreased with increasing nematode Pi, such that plant dry weight = 23g - 0.00015(Pi). Papaya genotypes differ in their response to M. javanica. The Hawaiian papaya cultivars are among the more susceptible genotypes to M. javanica. Damage caused by M. javanica is not especially severe on Sunrise papaya. Ten genotypes of semi-wild C. arabica were evaluated for resistance to Meloidogyne konaensis. Nine of the semi-wild genotypes had Rf values less than 1. The Rf values of the susceptible Typica and Yellow Catuai coffees were 13.1 and 15.95 respectably. The Rf value of the rootstock Fukunaga was 2.5. Some of the semi-wild coffee genotypes were very tolerant to infection whereas a few seemed to be intolerant. These semi-wild genotypes hold great promise for nematode control in coffee. ET15 (T.16704-7), ET17 (T.16706-6), ET 25B (17204-2). Due to the restricted host range of the nematode (only members of the Juglandaceae, and Quercus laurifolia), and the potential for dissemination in infected nursery stock, a study was conducted to determine the level of genetic variability among Meloidogyne partityla. M. partityla populations from AZ, GA, NM, OK, and TX were evaluated at the 5.8s rDNA and flanking ITS region and COXII tRNA His intergenic mtDNA region. None of the geographic locations showed significant variation in either sequence region within a location, so consensus sequences were produced for the 5.8s rDNA and mtDNA regions from each location. Neighbor-joining trees constructed for comparison of both loci across the five states, and with mtDNA sequences from Genbank, showed (as was anticipated) that greater variability among nematode populations was detected using mtDNA. Populations from NM and OK were highly similar to each other when comparing either locus, while populations from AZ, GA, and TX grouped similarly when the rDNA locus was used but the TX population separated from AZ and GA using the mtDNA locus. Sequence variation was generally very small, and no differences in behavior or pathogenicity among populations are known at this time. Cyst nematode on corn. A field on the KY-TN border has the same nematode as the find in 2006 in western TN. The only known commonality at this point is corn production and application of animal waste. Each of the three known occurrences of the nematode is at least 80 miles apart and no known link between the farms. Potato clones/varieties were screened for resistance to Columbia Root-knot Nematode and Corky Ringspot. Potato seed from 11 potato clones developed in the USDA-ARS Variety Development Program at Prosser, WA were compared to commercial varieties Ranger (R) and Russet Burbank (RB). Five clones had less than 5% of tubers expressing symptoms of CRKN compared to 20% and 55% for R and RB, respectively, and five clones had less than 5% of tubers expressing symptoms of CRS compared to 13% and 14% for R and RB, respectively. There was very little overlap in resistance to CRKN and CRS and only two clones (PA00N32-4, AOO646-4) had less than 5% CRKN and less than 5% CRS. The commercial varieties Yukon Gold, Canela, Rio Grande, Russet Nugget, Centennial, Russet Norkotah supported large population increases in CRKN with Russet Nugget having the greatest (200 fold) and Centennial the least (40 fold) increase. Centennial also had the least tuber damage (40% culls) compared to over 60% to near 90% in all other varieties. Expression of symptoms of CRS was high (>35%) in Yukon Gold, Canela and RioGrande, and low (<10%) in Centennial, Russet Nugget and Russet Norkoth. Determination of Nematode Adaptation Processes to Hosts, Agro-Ecosystems and Environments We are undertaking a morphometric and molecular characterization of genera and species of Criconemoidea. Samples from Florida, Missouri, North Carolina, Arkansas represent Mesocriconema, Criconema, Ogma, Tylenchulus (from grape in Missouri and Arkansas) Nothocriconema, criconemoides, Hemicycliophora, Hemicriconemoides, Paratylenchus, Gracilacus, Caloosia or R Loofia, Xenocriconemella and 4 more ring type nematodes for identification. Reserach on Helix aspersa (Cornu aspersum), the Brown Garden Snail, demonstrates that snails may serve as phoretic hosts for plant-parasitic nematodes. Morphological identifications of nematodes found in the snails include Aphelenchoides spp., Caenorhabditis spp., and Rhabditis spp., Aphelenchus avenae, Rhabditis terricola, Rhabditis bracisiae, and Panagrolaimus sp., Xiphnema spp., Aphelenchoides spp., and Aphelenchus avenae. The latter three nematodes are plant or fungal feeding nematodes and were recovered from the foot muscle and shell of the snail. No nematodes were recovered from the reproductive system or heart. The bacterial isolates from specific regions within the snail included preliminary matches to Serratia proteamaculans and Sphingobacterium kitahiroshimense, Stenotrophomonas maltophilia, and Serratia proteamaculans. P. putida, S. kitahiroshimense, and Escherichia coli and snail slime attracted C. elegans. Characterization of TN SCN field populations show an increase from 50% to 85% of the populations capable of reproducing on PI 88788. In the previous surveys there was no indication of the numbers of samples collected vs the number they were able to characterize. However, in the present survey, only a small percentage of samples contained or reproduced at a high rate for characterization. Pasteuria nishizawae has been recovered from field soil and a survey is currently underway. Although root-lesion (Pratylenchus spp.), cyst (Heterodera spp.) and northern root-knot (Meloidogyne hapla) are serious pests in Michigan, M. hapla is not considered economically significant in Michigan potato production. However, little information is available on the status of Michigan-grown potato cultivars against M. hapla. In view of the diverse Michigan cropping systems, movement of soil and plant material, and potential threats from quarantined nematodes (potato cysts and Columbia root-knot), it is necessary to examine the reaction of potato cultivars selected for Michigan conditions against M. hapla. The effects of four M. hapla populations (Mh 1, Mh 2, Mh 3 and Mh 4) collected from different soils and cropping systems in Michigan on three chipping (Boulder MSF373-8, MSJ461-1 and Kalkaska MSJ036-A) three tables stock (Jacqueline lee, Michigan Purple, and Snowden) potato cultivars and Rutgers tomato (control) were compared under controlled conditions. While infection was less than in tomato, the six potato cultivars were suitable hosts for the M. hapla populations. The results suggest that an M. hapla management strategy that includes a rotation of potato cultivars such as these may increase the risk to other crops. Difficult-to-control annual weeds serve as host reservoirs for M. incognita and Verticillium dahliae in the chile pepper (Capsicum annuum) system. Sspurred anoda (Anoda cristata = SA), tall morningglory (Ipomoea purpurea = TM), and Wrights groundcherry (Physalis wrightii =WG) experienced reductions in shoot or root weight in response to either M. incognita or V. dahliae. Growth of TM increased in response to infection by V. dahliae. The level of M. incognita reproduction was not reduced by V. dahliae infection of any annual weed, and increased on V. dahliae-infected SA. A microplot study of SA, TM, and WG to M. incognita infection will provide insight into the potential effect of root-knot nematode infection on the contribution of certain difficult-to-control annual weeds to the soil seed bank associated with these pests. Development and Assessment of Nematode Management Strategies in Agricultural Production Systems At the request of local producers, a study was initiated to evaluate the effectiveness of annual winter cover crops in combination with novel summer crops that were: 1) an aggressive growth habit likely to out-compete nutsedges (and/or broad registration of suitable herbicides for nutsedge suppression in the crop); 2) resistance to or poor host suitability for M. incognita; 3) potential for positive economic return to the producer. Oilseed radish (Raphanus sativus cv Boss) was selected as a winter cover crop. Cotton cv NemX HY, and a forage variety of pearl millet (Pennisetum typhoides cv Tifleaf) were selected for annual summer crops. A nondormant, M. incognita-resistant alfalfa cv Pioneer 58N57 was established as the positive control. Chile pepper will be planted as a high-value vegetable to assess the efficacy of previous crops in suppressing the weed/nematode pest complex at the conclusion of the study. Destroying Columbia root-knot nematode (Meloidogyne chitwoodi) in potato before processing will increase potato quality and address quarantine issues. Exposure of CRKNinfested tissues to chlorine in the form of bleach at concentrations up to 25,000 ppm Cl was ineffective. Boiling potato peels and water associated with peels for five minutes was effective but judged to be unacceptable to the industry. Heating potato peels and associated water to 60 ºC or above for one minute or longer was found to be an effective destruction protocol. Submersing whole tubers in water at 80 ºC for a minimum of three minutes before peeling was a reliable destruction protocol that would prevent escape of living CRKN through the peeling process. Short duration hot water treatments would be an effective method to destroy CRKN during processing. Temperatures of 50ºC (peels) to 70ºC (tubers) may be effective with longer exposure times but need testing. Studies include application of poultry litter and date of planting/MG study. In 2008 there was good correlation of NDVI readings with plant height and yield. No differences in SCN reproduction were observed in tillage or poultry litter rates. The 2009 data is still being processed. We try to communicate to producers that if they wish to continue soybean production over a number of years, they need to look at more than yield. We have included information for producers on the effects of varieties and date of planting on SCN reproduction. Effects of tillage strategies are ongoing. An undescribed bacterial parasite has been detected in this field area. Implementation of Rapid Information Transfer of Project Results to Stakeholder We timely extend information gleaned from the research objectives to a variety of clientele. Research results were disseminated to different user groups in several venues. Information is presented to extension specialists who incorporates the information into nematode recommendations. Information is also made available to agricultural producers, crop consultants, and county agents at conferences such as the Beltwide Cotton Conferences, the NM Crop Production Association; NM Vine and Wine Society; NM Chile Association Board of Directors; NM Chile Conference; and Joint AZ/NM Chile Association Field Day and the potato industry stakeholders. Results were transferred to scientific peers through presentations at national professional meetings such as the Society of Nematology/Soil Ecology Society, and the Weed Science Society of America and the Western Society of Weed Science. Results are published in peer-reviewed journals to disseminate information to scientific peers. The web is also used to present and share results of SCN screening of commercial soybean varieties.

Publications

Publications Attachment:

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Impact Statements

We have shown that a number of different nematode species may be associated with the common pest snail, including significant plant-parasitic nematodes, which allows movement of plant-parasitic nematodes between areas and relates to individual within-field pest management as well as international trade.
We have demonstrated that natural host-plant resistance genes are valuable in crop plants as effective and safe approaches to managing root-knot nematodes.
We have characterized genetic variability in nematodes for ability to reproduce on resistant plants and in so doing have helped guide decisions on use of resistant crop varieties and to give direction to plant breeding programs for grain legumes and cotton. New combinations of resistance genes hold promise for developing crop varieties with stronger and broader nematode resistance.
We have provided papaya breeders with genotypes that have been characterized for incorporation of greater nematode resistance into papaya cultivars. Papaya growers have additional information and quantified parameters to use in controlling and determining the necessity of control.
We have identified coffee genotypes provide important genes valuable in the coffee breeding. The coffee genotypes may be used immediately as rootstocks growers, possibly as cultivars for growers, and as parents in the coffee breeding program.
We have cautioned against the one-size-fits-all approach and provided growers with new and integrated information that they can use when selecting cultivars.
We have documented through analysis of rDNA and mtDNA loci from Meloidogyne partityla populations in North America that small-scale genetic differences exist among populations of the pecan root-knot nematode.
We have shown that growth of spurred anoda, Wright groundcherry, and tall momingglory - three significant annual weeds that damage southwestern chile pepper production and hosts of Verticillium dahliae and Meloidogyne incognita - was not adversely affected by infection or coinfection by both pathogens. Root-knot nematode reproduction on these weeds was not reduced by V. dahliae infection.
We have developed a protocol that would permit importing countries to destroy Columbia root-knot nematode (Meloidogyne chitwoodi) infected potato tubers before they are used and eliminate the risk of introduction of the nematode into their counties from tuber shipments with trace infection levels.
We have bred 2 potato clones showing promising resistance to Columbia root-knot nematode and corky ringspot. Host resistance will lead to fewer defects in tubers, less crop rejection, substantial savings to growers, and reduced nematicide use.
We have documented that none of the commercial potato varieties tested in Colorado had any resistance to Columbia root-knot nematode. However three varieties exhibited considerable resistance to corky ringspot and would be good candidates for planting in fields with a history of corky ringspot provided no nematode present.
We have detected Pasteuria nishizawae in soybean production fields and this helps explain low soybean cyst nematode egg population density and possibly slow reproductive rates of the nematode.

Date of Annual Report: 01/07/2011

Report Information

Annual Meeting Dates: 11/04/2010 - 11/05/2010
Period the Report Covers: 10/01/2009 - 09/01/2010

Participants

P. Donald, USDA ARS Tennessee;
R. Ingham, Oregon State University;
H. Melakelabrahan, Michigan State University;
T. Powers, Nebraska State University;
R. Robbins, University of Arkansas;
P. Roberts, University of California Riverside;
B. Sipes, University of Hawaii;

Guests;
G. Lawrence, Mississippi State University;
K. Lawrence. Auburn University;
V. Klink, Mississippi State University

Brief Summary of Minutes

Minutes Attachment:

Attachment

Accomplishments

Project activities are diverse and articulated in four objects. Project activities involve research spanning from basic molecular research into nematode genetics to nematode control in the field. Our accomplishments will be organized and reported under each of the four project objectives. Characterization of Nematode Genetic and Biological Variation Relevant to Crop Production and Trade Populations of Heterodera glycines across areas differ because of the soybean resistance deployed. SCN distribution increases exponentially with the deployment of resistant hosts. The longer plant resistance is used, the higher the proportion of populations which can reproduce on the standard sources of resistance.The greatest variability in H. glycines population characterization was in Ontario, Canada where plant resistance had been used for the shortest time period. A microarray comparative genomic analysis can identify genes of interest in resistant and susceptible soybeans which can then be used to affect nematode control in soybean and potentially other crops. Root-knot nematode is difficult to control in the many plants that are infected. However host-plant resistance is available. In papaya, Meloidogyne javanica reproduction ranged from 14 to 60 (with standard deviations from 21 to 96). Maradol, Kapoho, and breeding Line D had similar low Rf values. Sunrise, Saipan, and Vietnamese had similar Rf values twice as high as the Maradol group (Rf = 29). The last group of breeding lines average Rf values 3.5 times greater than the Maridol group. Currently, none of the widely grown potato cultivars are resistant to M. chitwoodi. New breeding lines with tuber- or rootspecific resistance genes from Solanum bulbocastanum are being evaluated. At present, the only available method to separate M. chitwoodi races and pathotypes is to conduct differential host test. These assays are time-consuming and cannot be performed with single nematodes. Our goal is to develop molecular methods to rapidly differentiate M. chitwoodi populations. Using microsatellites and random primers, we have found significant genetic diversity among M. chitwoodi races and pathotypes. We are currently trying to develop specific primers for sequence characterized amplified regions (SCAR) that would allow us to differentiate M. chitwoodi races and pathotypes by PCR. Rotylenchulus renifromis is also a challenging nematode to control. Twenty eight varieties of Vigna unguiculata, cowpea, were tested for host status to R. reniformis. Nematode Rf ranged from 0.04 to 1.17 on the cowpea after in screening in the greenhouse. The most resistant varieties were IT84S-2049, IT95K-1491 Danila, IT90K-284-2, IT98K-555-1, IT97K-499-39, and TVu7778. These plants had low Rf values and supported less than 205 eggs/g root tissue. The most susceptible cowpea tested was UCR 288. New soybean cultivars and breeding lines are evaluated for renifrom nematode resistance in Arkansas. Of the 161 varieties screened, 6 had with less reproduction than resistant varieties Hartwig and Anand and 5 are probably useful in a rotation. Of the 69 breeding lines evaluated, 12 were as good as the worst resistant variety. Determination of Nematode Adaptation Processes to Hosts, Agro-Ecosystems and Environments Nematodes seem to move into new areas with relative ease. The "ease" may actually be a reflection of our knowledge. A previously unrecognized M. chitwoodi pathotype has been identified that can overcome new potato resistance genes. Potatoes collected from local markets were infected by root-knot nematodes. As processing plants are reduced in number and become concentrated, tare soil is transported longer distances increasing the movement of nematodes. This can unintentionally introduce nematodes in to new areas. A recently identified population of Globodera is being evaluated for host range and other biological parameters. This population appears to be a new species. Rotylenchulus reniformis is correlated with soil type and water. As root biomass increases, so does the nematode population. It has become clearly important to kill cotton after harvest. This will prevent a final generation of R. reniformis from developing on the harvested cotton and increasing the total nematode population in the field. The identification of nematodes is important and large amounts of molecular data have been generated to identify nematodes over the last decade. The challenge is to now link data from the separate DNA markers like CO1, D2-D3, IGS, ITS, and 18s. This will aid in the identification of new species discovered from surveys and screenings. A nematode collection can be an invaluable resource in identifying new introductions or changes in a nematode over time. Maintenance of a nematode collection is not without expenses. Maintenance of living cultures is an expensive endeavor and cryopreservation is a less expensive alternative. However cryopreservation is not free. Funding is needed to support these valuable resources. Development and Assessment of Nematode Management Strategies in Agricultural Production Systems Nematode control is challenging for growers and producers. However our project is identifying tools and techniques that offer effective, environmentally sound and sustainable control. In a SCN rotation, Anand depressed the SCN population and gave higher yields. Rotating the resistance reactions will eventually reduce the SCN levels and not cause new SCN races to form. Pasteuria nishizawae has been found on SCN and can now be cultured in fermentation tanks. In open pollinated crops, F2 or later generations may not have the same levels of resistance as in the F1 or F0. We are finding evidence that such a loss may be occurring in the Coffea liberica used to control Meloidogyne konaensis. Implementation of Rapid Information Transfer of Project Results to Stakeholder In striving to rapidly disseminate information and knowledge generated by the project, we are increasing turning to electronic publication. The status of soybean cultivars to H. glycines are published on line. Information is also disseminated in traditional hard copy paper form. We are transferring findings to stakeholders via telephone, internet, mailings and publication, We are presenting at conferences, workshops and meetings. We are reaching growers, extension personnel, other scientists, and interested people employing these methods.

Publications

Publications Attachment:

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Impact Statements

Use or over use of plant resistance has driven nematode populations to more virulent races/biotypes/forms.
New technology has increased the potential of P. nishizawae as a biological control agent.
Host-plant resistance is found in crops like soybean, cotton, papaya and potato provide sustainable control options to growers.
The range in cowpea susceptibility to reniform nematode will allow breeders to ensure that cultivars with resistance to rootknot nematodes also have resistance to renifrom nematodes.
Nematodes are unintentionally transported in tare soil, with commodities, and with transplants and the incidence is generally not fully recognized.
M. chitwoodi races and pathotypes vary with some being parasitic on resistant sources.
Rapid and precise identification of nematode populations present in fields will avoid the loss of resistance genes.
Reniform nematode reduces cotton yield in excess of 30% and rotation with reniform nematode resistant soybean is an economicaly viable control option.

Date of Annual Report: 01/09/2012

Report Information

Annual Meeting Dates: 11/03/2011 - 11/04/2011
Period the Report Covers: 10/01/2010 - 09/01/2011

Participants

Ingham, Russ (inghamr@bcc.orst.edu) - Oregon State University;
Klink, Vincent (vk85@msstate.edu) - Mississippi State University;
Lawrence, Gary (glawrence@entomology.msstate.edu) - Mississippi State University;
Lawrence, Kathy (lawrekk@auburn.edu) - Auburn University;
Melakeberhan, Haddish (melakebe@msu.edu) - Michigan State University;
Powers, Thomas (tpowers1@unl.edu) - Nebraska State University;
Robbins, Robert (rrobbin@uark.edu) - University of Arkansas;
Roberts, Philip (philip.roberts@ucr.edu) - University of California Riverside;
Sipes, Brent (sipes@hawaii.edu) - University of Hawaii;
Thomas, Steve (stthomas@nmsu.edu) - New Mexico State University;
Thompson, David (dathomps@nmsu.edu) - USDA Administrator;

Brief Summary of Minutes

Minutes Attachment:

Attachment

Accomplishments

The project activities are covered in four objectives. Project activities involve research utilizing molecular tools and the application of the laboratory and greenhouse research into nematode control in the field. We have organized this year's accomplishments under the four project objectives. OBJECTIVE 1: Characterization of Nematode Genetic and Biological Variation Relevant to Crop Production and Trade Plant-parasitic nematodes have complex relationships with their host plants and these interactions can be confusing. The project has focused on three groups of nematodes the past year - Rotylenchulus reniformis, the reniform nematode, Meloidogyne, the root-knot nematodes, and Globodera, the round cyst nematodes. Reniform nematode limits yield of many important crops. In upland cotton, resistance was identified and incorporated into germplasm and releases as LONREN. The unique relationship between the nematode and the host plant has been demonstrated in LONREN. Whereas LONREN prohibits reniform nematode reproduction, at moderate nematode population levels plant reaction to the nematode is so severe as to cause yield reduction. In cowpea where root-knot nematode resistance is well defined, reniform nematode reproduction was variable. Several cowpea varieties with resistance to root-knot nematode appear to have resistance to reniform nematode as well. Reniform nematode resistance in soybean remains difficult to find, with most commercial and breeding lines being susceptible. Root-knot nematode resistance in grains, carrots, and cotton is often limited to a few genes and we need to direct efforts to expanding the base of resistance deployed in the field. Meloidogyne incognita reproduction on red-skinned potato cultivars differs and shows behavior similar to renifrom nematode on cotton. Some red-skinned potatoes are tolerant resistant whereas others are tolerant susceptible. It can be difficult to find Meloidogyne incognita, a root-knot nematode, resistance in corn hybrids. Of 40 hybrids examined, none are resistant. Meloidogyne hapla, a root-knot nematode, and the damage it causes to vegetable crops has been demonstrated to have a significant location-specific component. The pecan root knot nematode, Meloidogyne partityla, is challenging to control because of. Whereas the nematode host range is limited, the perennial nature of the pecan host renders most rotation options moot. The discovery of Globodera palida in Idaho several years ago prompted surveys across the region to identify other areas of infestation. While no other infestations were found, a new species of Globodera was identified. This species, not of regulatory concern, has only been identified in a limited geographic area. This new species has strong diapause and appears to be responsive to stimulation from solanaceous plants. Its biology has limited our progress in delimiting its host range and documenting its damage potential. OBJECTIVE 2: Determination of Nematode Adaptation Processes to Hosts, Agro-Ecosystems and Environments Information on nematode identification and phylogenetics (concentrating on the Criconematid) is especially important was we experience climate change and possible changes in cropping systems. A 635 bp 3' region of 18S rDNA has been used to bar code nematodes. With nematodes, the differentiation of species and their classification is at times extremely important (for resistance and rotation based control) and at other times less important (with the use of nematicides). As plant-nematologists, we struggle with what is needed to separate species-morphological differences, molecular differences, host range, or its pathogenicity. A Meloidogyne species isolated from guava in Thailand was found to have variable perineal patterns, a VS1-S1 esterase phenotype, and a COII primer fragment of 700 bp. These characteristics show the species to be Meloidogyne enterolobii, a first report of the species in Thailand. The utility of molecular diagnostic tests continues to expand. A test has been developed for reniform nematode in soil using a quantitative PCR (qPCR)-based assay. The qPCR procedure accurately detects the reniform nematode as well as estimating the number of nematodes from metagenomic DNA isolated from the same soil sample. OBJECTIVE 3: Development and Assessment of Nematode Management Strategies in Agricultural Production Systems Crop rotation remains tried and true approach for nematode control in many cropping systems. Generally rotations that cycle over several years are more effective than our common 1-year rotations. Rotations that strive to control mixed nematode mixed populations, such as root-knot and reniform in cotton, are especially challenging. Effective rotations employ alternate and non-hosts in addition to resistance genes. Planting the same crop in consecutive years, consistently results in lower yields in most all cropping systems. Precision agriculture can be used to effect nematode control. Research as demonstrated that nematicide rates can be targeted to nematode population densities with a subsequent reduction in total pesticide used. However, the challenge remains in the economic assessment nematode population densities in the soil. Water availability throughout the growing season should be considered in risk assessment when creating site-specific management for nematodes, especially the reniform nematode. Research into biological control alternatives for nematodes continues on several fronts. Bacillus firmus strain GB-126 (Votivo® by Bayer) reduces the number of vermiform life stages of reniform nematodes in the soil, and the number of females infecting roots. Consequently, lower number of eggs per gram of root are produced. While not sufficient to protect the crop from damage, the reduction in nematode population may have utility in shortening rotations and allowing resistance to be more effective. OBJECTIVE 4: Implementation of Rapid Information Transfer of Project Results to Stakeholder The project employs a variety of venues to convey information to our varied stakeholders. Current nematicide and variety tests are published university web sites. Information is also delivered at annual meetings of professions as exemplified by Cotton Belt meeting, society meetings like the Society of Nematologists, and grower meetings. Information is published in scientific and lay journals. A web service is currently being developed in which the end user can upload ground or sub-orbital hyperspectral reflectances of their fields and see the results of the prediction models in an easy to use interface. The inclusion of a web service to this project increases the impact of this project.

Publications

Book Chapters Lawrence, K. S. and G. W. Lawrence. 2009. Chapter 14: Pest Management: Nematodes. In Conservation Tillage Systems: Production, Profitability and Stewardship. eds Bergtold, J. , Raper, R. , Hawkins, G., and Iversen, K. CRC Press LLC. Klink V.P., P.D. Matsye, and G.W. Lawrence. 2010. Cell-specific studies of soybean resistance to its major pathogen, the soybean cyst nematode as revealed by laser capture micro-dissection, gene pathway analyses and functional studies. Soybean. Intech Publishers. Pp 1-32. Klink V.P., P.D. Matsye, and G.W. Lawrence. 2010. Developmental genomics of the resistant reaction of soybean to the soybean cyst nematode. Modern Concepts in Functional Genomics. Plant Tissue Culture and Applied Plant Biotechnology Chapter 10: pages 249-270. Journal Articles R.Y.M. Cabos, B.S. Sipes, C. Nagai, M. Serracin and D.P. Schmitt. 2010. Evaluation of coffee genotypes for root-knot nematode resistance. Nematropica 40:191-202. Doshi, R. A., R.L. King and G.W. Lawrence. 2010. Classification of Rotylenchulus reniformis numbers in cotton using remotely sensed hyperspectral data on self-organized maps. Journal of Nematology:42 179-193 Skantar, A.M., Handoo, Z.A., Carta, L.K., Zasada, I. A., Ingham, R.E., Chitwood, D.J. 2011. Morphological and molecular characterization of Globodera populations from Oregon and Idaho. Phytopathology. 101:(4)480-491. Proceedings Bennett, R.S., A.L. Bell, J.E. Woodward, K.S. Lawrence, C.S. Rothrock, T.L. Kirkpatrick, G.W. Lawrence, P.D. Colyer, and R.M. Davis. 2011. Report progress on a contemporary survey of the Fusarium wilt fungus in the United States. Proceedings of the National Beltwide Cotton Conference, Vol. 1, National cotton Council, Memphis TN. Online: www.cotton.org/beltwide/proceedings. Lawrence, G.W. K.S. Lawrence and B Haygood. 2011. Efficacy of Dow AgroSciences seed treatment fungicide STP 20143 for the management of the seedling disease complex of cotton. Proceedings of the National Beltwide Cotton Conference, Vol. 1, National cotton Council, Memphis TN. Online: www.cotton.org/beltwide/proceedings. Lawrence, K.S., G.W. Lawrence and S.R. Moore. 2011. New nematicide potentials in cotton in the southeast and mid south. Proceedings of the National Beltwide Cotton Conference, Vol. 1, National cotton Council, Memphis TN. Online: www.cotton.org/beltwide/proceedings. Murray, L , S.H. Thomas, J. Schroeder, S. Kreider, Z. Du, J.M. Trojan and C. Fiore. 2011. Modeling the root-knot nematode/nutsedge pest complex: perspectives from weed science, nematology and statistics. Proceedings of the 2011 AgStat Conference (in press). Robbins, R. T., E. Shipe, P. Arelli, P. Chen, G. Shannon, K. M. Rainey, L. E. Jackson, E. E. Gbur, D. G. Dombek, & 1. T. Velie. 2011. Reniform nematode reproduction on soybean cultivars and breeding lines in 2010. Proceeding of the 2011 Beltwide Cotton Conferences, Atlanta, Georgia, January 4-7, 2011, Pgs. 167-174. Abstracts Bernard, E.C., I.M. Trojan, and S.H. Thomas. 2011 . Nematode biodiversity at Otero Mesa, New Mexico, a pristine desert grassland. Journal of Nematology 43: (in press). Brito, IA R.A Stamler, S.H. Thomas, AP. Nyczepir, and D.W. Dickson. 2011 Distribution, hosts and identification of Meloidogyne partiryla in the USA. Nematropica 41: (in press). Kandouh, B. and B. Sipes. 2011. Red potato cultivar (Solanum tuberosum L.) susceptibility to the root-knot nematode Meloidogyne incognita. Phytopathology 101:Supplement. Lawrence, K. S., G. W. Lawrence, V. Klink, and S. Moore. 2011. Host status of soybean differential genotypes to Rotylenchulus reniformis and Meloidogyne incognita race 3. Phytopathology 101:S99. Lawrence, K. S., S. R. Moore, W. S. Gazaway, G. W. Lawrence, J. R. Akridge. 2011. Evaluation of cotton varieties with TeloneII for reniform management in cotton in south Alabama, 2010.Report No. 5:N006 DOI: 10.1094/PDMR05. The American Phytopathological Society, St. Paul, MN. Lawrence, K. S., S. R. Moore, G. W. Lawrence, C. H. Burmester, C. Norris. 2011. Evaluation of seed treatments and seed quality in cotton seedling disease management in Alabama, 2010. Report No. 5:ST022 DOI: 10.1094/PDMR05. The American Phytopathological Society, St. Paul, MN. Lawrence, K. S., S. R. Moore, G. W. Lawrence, C. H. Burmester, C. Norris. 2011. Evaluation of experimental seed treatments in cotton seedling disease management in Alabama, 2010.Report No. 5:ST021 DOI: 10.1094/PDMR05. The American Phytopathological Society, St. Paul, MN. Makimoto, Y. and B. Sipes. 2011. Innate response in tissue cultured Anthurium andraeanum against Radopholus similis. Phytopathology 101:Supplement. Robbins, R. T., and L. E. Jackson. 2011. Soybean varieties and breeding lines shown with resistance to reniform nematode in greenhouse tests, 1998-2010. Proceeding of the Southern Soybean Disease Workers. Fort Walton Beach, FL. Robbins, R. T., E. Shipe, P. Arelli, P. Chen, G. Shannon, K. M. Rainey, L. E. Jackson, E. E. Gbur, D. G. Dombek, and J. T. Velie. 201 1. Reniform nematode reproduction on soybean cultivars and breeding lines in 2010. Proceedings of the Beltwide Cotton Conferences. Atlanta. Thomas, S.H., J.M. Trojan, and R.I. Heererna. 2011. Meloidogyne partiryla-induced changes in pecan growth and nutrient sequestration. Journal of Nematology 43: (in press).

Impact Statements

"The difference in host response of the crops (resistance/susceptibility and tolerance/intolerance) to plant-parasitic nematodes demonstrates the importance of continual variety examinations.
"The lack of resistance to root-knot and reniform nematodes in many crops (such as corn, cotton, and soybean) warrants continued screening of cultivars available to our producers.
"Rotations with non-host crops continue to play a major role in nematode management.
"More emphasis is needed to quantify the role of soil conditions in nematode damage to crops.
"Public awareness on soil health management has increased.
"Cotton cultivars resistance to Meloidogyne incognita are available to our growers and these cultivars are also less susceptible to Fusarium wilt.
"Precision nematicide application can enhance yield in nematode infested fields.
"Biological nematicides are becoming available and they appear to reduce subsequent generations of nematodes.
"Cultivar selection is important to minimize nematode damage in crops.
"Breeders, both at public and private institutions, have information available to incorporate resistance to nematodes in cotton, soybean, cowpea, and pecan.
"Molecular tools are becoming more practical for the identification of nematodes in field soil.
"Molecular tools have been used to identify Meloidogyne enterolobii infecting guava.

Date of Annual Report: 01/02/2013

Report Information

Annual Meeting Dates: 10/31/2012 - 11/02/2012
Period the Report Covers: 10/01/2011 - 09/01/2012

Participants

Brief Summary of Minutes

Minutes Attachment:

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Accomplishments

The scientists participating in the project, along with their students and support staff, and in many cases private collaborators, brought their collective knowledge and experience to address nematodes affecting trade. Activities in the laboratory, greenhouse, and field have demonstrated how growers and producers can minimize the impacts that nematodes have on trade. This years accomplishments are presented under the four project objectives. Objective 1: Characterization of Nematode Genetic and Biological Variation Relevant to Crop Production and Trade The primary focus of the project has been to provide protocols for rapid and accurate identification of nematodes by state and federal inspectors, scientists, and diagnosticians. PCR primers for COI have been designed and modified for root-knot, cyst, and genera of ectoparasitic nematodes. Little genetic variation was detected among geographically diverse Ditylenchus dipsaci populations recovered from garlic in Oregon, Ontario, Canada, and the Republic of Georgia. Whereas agricultural and native isolates of Criconematidae revealed extensive genetic differentiation within traditionally accepted morphospecies. Project scientists are using the ²-tubulin gene in a metagenomic DNA isolated directly from soil to quantitatively measure plant-parasitic nematode infestation levels. In addition to the ²-tubulin gene, a series of Heterodera glycines expressed genes are being evaluated in the laboratory for metagenomic analyses of soil population densities. Surveys are important for knowing what nematodes are present in an area. Knowledge of the distribution of nematodes is important for their management and control. In Tennessee, 82% of samples had plant-parasitic nematodes including: Heterodera glycines (16%), Meloidogyne incognita (4%), Pratylenchus sp. (19%), Helicotylenchus (50%), Tylenchorhynchus sensu lato (11%), Rotylenchulus (3%); Hoplolaimus magnistylus was detected in soybean, corn and cotton fields but at low levels. Our survey efforts have identified a putative M. graminicola and an undetermined Meloidogyne species on purple nutsedge (Cyperus rotundus) in an agricultural setting and on alkali sacaton (Bouteloua trifida) in native vegetation. Globodera ellingtonae has been described from samples collected 4 years ago. G. ellingtonae is morphologically and molecularly distinct from golden potato cyst (G. rostochiensis), pale potato cyst (Globodera pallida), and tobacco cyst (G. tobaccum). Surveys of banana and corn in Thailand and Hawaii identified included Pratylenchus coffea (Thialand), P. brachyurus (Thialand and Hawaii), P. speijeri (Thialand), and an unknown Pratylenchus species (Thialand and Hawaii). Host-plant resistance in cultivars of our food crops is the most economically and ecologically sustainable approach to nematode management. In initial tests, G. ellingtonae did not result in significant yield loss in potato although potato root exudate stimulated egg hatch. Resistance to G. ellingtonae was identified in potato varieties with the G. rostochiensis Ro1 resistance. Many red-skinned potato cultivars (All Red, Durango, Desiree, Pink Pearl, and Colorado Rose) were susceptible to Meloidogyne incognita, however some cultivars (Rote Ersting and Mountain Rose) exhibited some level of resistance to M. incognita. Desiree was moderately tolerant to both M. javanica and M. konaensis, but intolerant to M. incognita. Red Thumb was the most susceptible/intolerant cultivar to M. incognita, and the most resistant/intolerant to both M. javanica and M. konaensis. There are resistance genes which can be exploited in these cultivars. Ren1 confers resistance to Rotylenchulus reniformis in cotton. The cotton lines with Ren1 tested were stunted during early season growth and yielded less than their sister lines null for Ren1 in the nematode-infested field. Nematode populations were reduced in plots where lines with Ren1 were planted. Lines carrying Ren1, however, tended to have greater fiber strength, better uniformity and lower short fiber content. Of 157 soybean varieties tested, only 7 (JTN-4408, REV®55R83, JTN-5110, AgBorn S06-X79464, ARMOR 49-C3, JTN-4307, ARMOR 50-C3) supported the same low level of R. reniformis reproduction as the resistant cultivars Forrest, Hartwig, and Anand. These soybeans have rotation usefulness. Of 97 public varieties and breeding lines, 24 were as good as the resistance found in the cultivar Forrest for R. reniformis. Twenty eight cowpea lines with resistance to M. incognita previously challenged with R. reniformis populations from Hawaii and Alabama did not have resistance to an Arkansas population of R. reniformis populations either. Another approach project scientists are investigating for identification of resistance is gene expression, particularly those genes expressed in nematode feeding sites. Genes from H. glycines have been engineered into Williams 82 soybean and will be used to identify the functionality of genes involved in defense responses. Nematodes are genetically variable and variability can manifest itself in nematode adaptation to specific soil ecosystems. Thus integrating nematode adaptation and variability into site-specific management strategies should provide producers better tactics for control. Populations of Meloidogyne hapla varied in reproduction and virulence on celery, tomato, potato, and carrot cultivars. In all cases, a M. hapla population isolated from a sandy soil was the most pathogenic. The varying degree of host suitability, however, suggests that the severity of the problem will likely vary by cultivar and population of M. hapla. Identifying the reproductive potential of a M. hapla populations is critical to making site-specific management decisions. Objective 2: Determination of Nematode Adaptation Processes to Hosts, Agro-Ecosystems and Environments Nematodes are often found to behave in unexpected ways. A putative M. graminicola recovered from purple nutsedge produced readily-apparent galls on nutsedge roots, unlike the more commonly encountered M. incognita, which rarely induces galling. Egg masses of M. incognita, however, were readily evident on the surface of infected roots, while those of M. graminicola were nearly always smaller and submerged within the root cortex. Nutsedges infected with M. graminicola were only observed in heavier-textured loam and clay loam soils whereas M. incognita was absent. However, M. graminicola populations were well adapted to survival in aloamy sand soil under microplot conditions. In preliminary greenhouse experiments, the putative M. graminicola failed to reproduce on tomato. Deployment of resistance can place strong selection pressure on the nematode population, ultimately resulting in the loss of effective resistance. Our focus is to understand and manage the deployment of resistance for long term utility. Planting H. glycines- susceptible soybean had no detectable selection on virulence phenotype. When the initial H. glycines population was avirulent, PI 88788-derived cultivar selected a population that overcame PI 88788, and the Peking-derived cultivar selected nematode populations that overcame the resistance in Peking. In contrast, the PI 437654-derived cultivar selected nematode populations that increased reproduction on both PI 88788 and Peking sources of resistance. The NIL-R selected a nematode population that overcame PI 88788 and increased reproduction on Peking. When the initial H. glycines population was virulent on PI 88788, both Peking- and PI 437654-derived cultivars increased reproduction on Peking. No selected population overcame the resistance found in PI 437654. In a long term experiment, H. glycines populations had positive correlations with total nematode abundance, total non-H. glycines nematode abundance, free-living nematode abundance, and bacteria-feeding nematode abundance, suggesting that conditions favoring free-living nematodes can also favor H. glycines. Analysis suggests that in addition to direct impacts, tillage and susceptible cultivar may have indirect impacts on increasing H. glycines population densities through favoring free-living nematodes, while crop rotation is likely to have an indirect impact in decreasing H. glycines through decreasing free-living nematodes. In a soybean cultivar rotation following the cultivar Anand, the H. glycines population was lowered and shifted from race 6 to race 5. In this rotation, soybean yields were higher. A new rotation scheme using moderately and highly resistant soybean cultivars is being initiated to determine rotation schemes that maximize producer profit. Objective 3: Development and Assessment of Nematode Management Strategies in Agricultural Production Systems Management of plant-parasitic nematodes can take the form of pesticide applicationsboth chemical and biological, as well as cultural practices. A low rate of the the fumigant 1,3-dichloropropene, 200 ppm, suppressed M. incognita population densities by 96% in treated grapevines compared to nontreated. Grape quality was also improved with higher brix and lower malic acid content in those vines receiving the fumigant. Nematicide seed treatments are being marketed in crops like cotton and soybean. Field tests trended toward higher yields in treated soybean but no effect on H. glycines reproduction. New chemicals for nematode management are being introduced. On sugar beet infected with H. schachti, combinations of Poncho 600 FS, Poncho Beta FS, Votivo, and Movento increased sugar beet yield by 13 to 23% as compared to the untreated control. The application of Admire, Movento, and Sepresto, alone and combined, for Pratylenchus sp. control increased onion yield by 15% to 70 % as compared to the untreated control and generally produced greater yield than in onion plants treated with the old standard Vydate. MCW-2 (fluensulfone) increased onion yield compared to the untreated control. MCW-2 was also effective against M. chitwoodii and Paratrichodorus on potato compared to an untreated control. Application of MCW-2 in combination with Vydate was an effective management practice for nematodes infecting potato nematodes. Nonchemical tools can be used to manage nematodes inside plant tissue. Nematodes infecting plant tissues can be challenging to eliminate which is especially important for quarantine nematodes. Potato tubers infected with M. chitwoodi that were irradiated with either Cobalt 60 or linear accelerator experienced dramatic decreases in survival. Due to increased restrictions on the use of chemical nematicides, alternative nematode management strategies, including biocontrol, must be developed. Bacillus firmus GB-126 and Paecilomyces lilacinus 251 are two such possible organisms. Cotton seeds treated with B. firmus (1.4 x 107 cfu/seed), or an application of P. lilacinus (0.3% v/v of water), and the combination of both reduced the number of females, eggs, and vermiform life stages of R. reniformis and increased populations of free-living nematodes. Field populations of R. reniformis decreased when exposed to both biocontrol agents. Furthermore, cotton stem diameter and free-living nematode numbers increased with both biocontrol agents. Cotton yields in B. firmus GB-126- and P. lilacinus 251-treated plots were similar to those in aldicarb-treated plots. The time required to screen plant accessions for resistance to nematodes like M. incognita can take months and any shortening of the time would be beneficial. However, the use of shoot cuttings in crops like chile pepper has not been effective as a method to evaluate plants for nematode resistance. Site specific nematode management is becoming more feasible each season. The application of nematicides using variable rate technology requires knowledge of the intra-field variability of the nematode population, which depends on the collection of soil samples and analysis of these samples for nematodes in the laboratory. Hence estimating the nematode infestation using remote sensing and machine learning techniques can be both cost and time effective. Soil texture is currently being explored as a basis for the development of economic thresholds for R. reniformis and creating management zones within cotton fields. Populations of R. reniformis were influenced by soil texture and exhibited a general decrease with increasing median soil particle size. Soil texture in combination with other soil properties will become a useful tool for developing management strategies for R. reniformis on cotton. A web service is currently being developed in which the end user can upload ground or sub-orbital hyperspectral reflectances of their fields and see the results of the predictive models in an easy to use interface which is graphically appealing. Objective 4: Implementation of Rapid Information Transfer of Project Results to Stakeholder Our efforts in rapid information transfer have fallen into two primary areasmeeting presentations and web access. Research results are disseminated to different user groups through presentations at their meetings. Our findings have been presented at national meetings attended by producers, scientists, and professionals. We have made presentations to state and federal regulators. We have presented our results at field days and extension meetings. We also disseminate information to smaller groups through facility tours, email, telephone conversations, and tradition hard copy. Information and findings are published on university web sites.

Publications

Publications Attachment:

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Impact Statements

Unknown species of nematodes have been discovered and new hosts identified for known species of nematodes.
Soil texture in combination with soil moisture can be a useful tool for developing management zones for precision nematicide applications.
Bacterial and fungal biological nematicides are becoming available.
Simple and reliable molecular techniques allow identification of nematodes.
Low-dose application of 1,3-Dichloropropene provides producers a tool to suppress root-knot nematode.
New nematicides (Admire, Sepresto, Poncho, Votivo, Movento , and MCW-2) are effective components of a nematode management program.
The Ren1 gene in cotton is effective in reducing reniform nematode populations.
Strategic deployment of resistance can manage nematodes over the long term.
A web-based service for nematode detection is available.
Irradiation of potato tubers combined with diligent management practices in the field and thorough inspection protocols effectively prevent introduction of Columbia root-knot nematode into new areas.
Agro-biologically based timeline information is critical for nematode management.