Brief Summary of Minutes of Annual Meeting

Harald Scherm  Administrative Advisor oversaw the annual meeting and provided guidance and information on the renewal process. To date 15 members are signed up for the new S1053. As S1028 has come to a close a termination report will need to be prepared. When discussing future directions for the research group, emphasis on collaborative proposal development was suggested as an area the group could work together to improve on from the last project period. Those in attendance included: Sheng Yu - Mississippi State University Kurt Lamour  University of Tennessee Kirk Broders  University of New Hampshire Craig Rothrock  University of Arkansas Carla Garzon  Oklahoma State University Craig Canaday  University of Tennessee WTREC Louisa Santamaria  Oregon State University After introduction, each member in attendance provided a presentation and update of current ongoing research and results from the past year associated with the project. At the conclusion of the presentation, the group came to a consensus to hold next years meeting of the S1053 multi-state group in Oklahoma City, OK around the first week of November. Kurt Lamour was nominated for Secretary and a unanimous vote confirmed his new post. As secretary, Kurt is also the Chair-elect. Kirk Broders will be the incoming Chair, and Craig Rothrock is the outgoing chair. The final topic of discussion was how we can better integrate projects by individual investigators to tackle larger problems that require a multi-state effort to accomplish. Some of the ideas put forth included: Chloride and relationship to Pythium P. capsici distribution and management Pythium taxonomy and describing non-spore forming species Disease complexes symposium/workshop Rhizoctonia population resources International Potato Center for Rhizoctonia resources Meeting adjourned.

Objective 1. Examine commercial and non-commercial biocontrol agents for use as seed treatments, in-furrow treatments or as potting mix amendments. A regional trial of biocontrol agents and amendments for control of wire stem of broccoli (Rhizoctonia solani) was conducted at five sites in four states (KY, TN-Knoxville, TN-Jackson, AR, and SC) over multiple years. Eight treatments were evaluated; millet seed infested with binucleate-Rhizoctonia (BNR), Monarda herbage, BioYield Flowable, Beauveria bassiana isolate 11-98, Actinovate AG, an untreated control, and a fungicide standard. Positive responses included: Jackson, TN (Canaday) all materials reduced the incidence of Rhizoctonia root rot or Pythium root rot compared to the untreated control and plant growth-promoting rhizobacteria (PGPR) were equal to the fungicide standard for disease control and in another year the PGPR product BioYield Flowable increased head weight of some broccoli cultivars. In eastern TN (Ownley), broccoli seed treated with Beauveria bassiana 11-98 (1,000,000 spores/seed), followed by planting into potting mix containing 2% bioactive dried Monarda herbage resulted in equal or greater head size and yield weight than the standard fungicide treatment and greater than other treatments evaluated. In South Carolina (Keineth), application to potting mix of Monarda herbage (2% w/w) and BioYield Flowable increased broccoli plant height at 50 days after transplanting compared with the pathogen-infested control. In another year, Keinath, a non-pathogenic (binucleate) Rhizoctonia isolate and BioYield Flowable significantly increased the percentage of disease-free broccoli plants and reduced the number of plants with wirestem 30 days after transplanting. Additional biocontrol studies were conducted by individual participants. Benson (NC): Binucleate Rhizoctonia (BNR) isolates BNR621 and P023, and Trichoderma hamatum isolate 382 induced resistance to the foliar fungal pathogen Botrytis cinerea in geranium. Canaday (TN): The combination of BioYield and fungicide treatments with and without application of Actigard had no effect on the incidence of stem rot (Sclerotinia sclerotiorum) and buckeye rot (Phytophthora nicotianae) affecting tomato. Canaday (TN): In field tests in soils natural infested with R. solani, Pythium spp., Macrophomina phaseolina, and Fusarium spp., GB03 or MBI600 used alone or as supplements to standard seed treatment chemicals, failed to increase snap bean stand or yield. Additional evaluations found response to Bacillus subtilis (MBI600) when added to fungicide seed treatments for control of seedling diseases of spring-planted snap beans varied with the cultivar used. For soybean, the percentage of disease-free plants was greatest with a seed treatment combination of the PGPR strain Bacillus subtilis MBI 600 and the fungicides mefenoxam and fludioxinil. Ownley (TN): Beauveria bassiana 11-98 endophytically colonized tomato and cotton following seed treatment. The extent of colonization was dependent on seed treatment rate and host plant. Plant colonization by B. bassiana was essential for disease control. Application of Beauveria bassiana 11-98 to seedling roots induced systemic resistance in cotton leaves against the bacterial pathogen Xanthomonas axonopodis pv. malvacearum. Integration of Beauveria (B. bassiana 11-98 or BotaniGard) seed treatments and RootShield (Trichoderma) provided mixed results on tomato seedlings in soil infested with Rhizoctonia solani or Pythium myriotylum. Padgett (LA): Biological fungicides when applied alone and in combination with strobilurin fungicides on wheat, corn, and soybean were not effective for managing diseases or preserving yields when applied alone. Seebold (KY): Bioten, a commercial formulation containing Trichoderma harzianum and T. viride, significantly reduced Phytophthora blight, caused by Phytophthora capsici, on summer squash when applied to soil via drip irrigation (25% to 60% reduction over the untreated control), while Ridomil Gold reduced incidence by at least 60% to 90% compared to the untreated control. Elliot (FL): Container-grown Mexican fan palm (Washingtonia robusta) and queen palm (Syagrus romanzoffiana) treated at the time of planting with four commercial microbial inoculants (each containing arbuscular mycorrhizal fungi, either alone or with other microbial components or fertilizers), or two fertilizers did not improve growth over the control in the P-deficient soil or P-sufficient soil. Keinath (SC): The commercial biofungicides RootShield and Actinovate were tested for prevention of damping-off of arugula on a noncertified organic vegetable farm in Charleston County, South Carolina. Fresh weight of arugula harvested 1 month after seeding did not differ among treatments. Discovery of new biological control agents were examined as part of the project. Lu (MS): Occidiofungin from the bacterium Burkholderia contaminans strain MS14 was evaluated regarding its stability and efficacy as an antifungal compound. Functions for the genes in the 56-kb occ gene cluster that is essential for production of occidiofungin was examined. Interestingly, disruption of the ocfC gene in the ocf gene cluster by the insertion of the nptII cassette resulted in xylose-free occidiofungin production and reduction of antifungal activity against the indicator fungus Geotrichum candidum. However, the antifungal activity of the xylose-free occidiofungin was significantly increased against Candida species as compared with the wild-type occidiofungin. These results are significant for development of agricultural biofungicides and medical parametrical drugs. In addition, more than 60 bacteria from 900 isolates obtained from Mississippi soils exhibited significant antifungal and/or antibacterial activities against pathogenic fungi and bacteria. Garzon (OK): A study of bacterial communities present in Andean soils from Ecuador suppressive to Phytophthora infestans was conducted. Approximately 3,000 bacterial strains of Bacillus, Pseudomonas, and Actinobacteria (including Streptomyces) were isolated and evaluated for their ability to inhibit P. infestans and Rhizoctonia solani. Strains with stronger inhibitory effects were selected for further characterization, and 200-300 strains of each bacterial group were sequenced (16S rDNA). Currently, the microbial communities in these soils are under further examination using metagenomic methods. Backman (PA): Endospore-forming bacterial endophytes were isolated from Theobroma cacao. Cacao leaves, pods, branches, and flower cushions were removed from cacao trees escaping disease and tissue was surface sterilized, heat treated (75°C for 15 min), and plated. 69 endophytic endospore-forming bacteria were isolated. Sixteen isolates were chitinolytic and in antagonism studies against cacao pathogens, 42% were antagonistic to Moniliophthora roreri, 33% to M. perniciosa, and 49% to Phytophthora capsici. 25% of isolates inhibited the growth of both Moniliophthora spp., while 22% of isolates inhibited the growth of all three pathogens. All 14 isolates were capable of endophytic colonization; while 8 isolates significantly inhibited P. capsici lesion formation in detached leaf assays. Ojective 2. Examine the effect of cultural practices on soilborne pathogens and plant growth The value of mulch or cover crop amendments were examined for a number of cropping systems. Benson (NC): Phytophthora root rot of Fraser fir, caused by several Phytophthora spp., is a severe problem in Christmas tree production. Treatments included wood chips, wood chips plus compost, or pine bark as raised beds, and compost or sulfur tilled into soil. Bacterial and fungal counts, microbial activity, and cellulase activity were higher in mulch than in soil at all sites and times (P<0.01), and generally did not differ among mulch types or among soils. Treatments significantly affected disease ratings and tree survival at three of five sites, with one or more mulch treatments yielding lower disease ratings and greater survival than controls. Tree mortality at each time point varied significantly with cellulase activity in the upper root zone (P=0.005). Ownley (TN): Anaerobic soil disinfestation (ASD) treatments were applied to soil in growth chamber pot studies to determine effects on populations of Rhizoctonia solani, and growth and disease of a subsequent broccoli crop. Cover crops were hairy vetch, arugula, wheat, cereal rye, crimson clover, and mustard. Irrigation following cover crop incorporation is an important component of the ASD method in order to achieve anaerobic soil conditions. In trial 1 (with irrigation, ASD treatment), broccoli from soil mixed with chopped hairy vetch were twice as large (weight) as the fallow control, and were equally low in disease rating and propagule counts of R. solani in soil as the control. In trial 2 crimson clover, wheat, and hairy vetch resulted in broccoli shoot height that was the same as the fallow control plants. Rhizoctonia populations were equally low in the fallow and wheat soil treatments, while disease rating of broccoli was lowest, and not different from the fallow control, with hairy vetch, wheat, crimson clover, and cereal rye ASD treatments. Keinath (SC): Cahaba White vetch reduced the number of wilted seedless watermelon plants in one of two experiments. An on-farm trial was done to evaluate the effects of cover crops and fumigants on Fusarium wilt and yield of seedless watermelon. The two fumigants, 67% methyl bromide-33% chloropicrin and Telone-C35, both combined with hairy vetch (Vicia villosa), were more effective than hairy vetch or rye alone or fallow at increasing yield. Oilseed radish (Raphanus sativus), mustard (Brassica juncea cv. Pacific Gold), and winter rapeseed (B. napus cv. Dwarf Essex) were incorporated as biofumigation cover crops. After incorporation, plots were covered with white-on-black virtually impenetrable film (VIF). Control treatments were fallow with and without VIF. Isothiocyanate concentrations (ITCs) in soil were higher after incorporating fall-planted vs. spring-planted Brassicas. Five weeks after incorporation, populations of Pythium spp. and Sclerotium rolfsii did not differ among treatments. Populations of Rhizoctonia solani were higher in fallow without VIF than in all mulched treatments, indicating that the VIF reduced populations of R. solani. Pepper plants transplanted into the plots were stunted due to infection of the roots in all plots by Pythium aphanidermatum but particularly in the fallow plots without VIF. Pepper yields were consistently highest in Brassica treatments compared with fallow with VIF. Rothrock (AR): The winter cover crop Indian mustard cv. Fumus reduced seedling root and hypocotyl disease symptoms. Brassica amendments also reduced early season galling from the root-knot nematode similar to the Telone treatment. Brassica treatments improved cotton yield over the control and were similar or greater than the Telone treatment in both the root-knot and reniform nematode infested locations. In other studies, rate of Brassica application had the greatest impact on disease symptom reduction and reducing Rhizoctonia solani isolation. A summer brassica cover crop, mustard seed meal amendment, solarization or a combination of the cover crop and solarization were compared to no soil treatment prior to establishing an annual strawberry crop. In all cases, there was a trend for higher bacterial, fungal and actinomycete populations in brassica, brassica plus solarization and mustard seed meal amended soils compared to solarized only and control soils. Total culturable bacterial populations were significantly higher in soils that had been planted with a brassica cover crop followed by solarization and soils receiving mustard seed meal amendments. From soil samples taken at 7 and 25 days after the brassica cover crop was incorporated and at the time of strawberry transplant, bacterial DGGE profiles of soils receiving different treatments were distinct and grouped separately in dendograms. Gentry (TX): The effect of oilseed meals from both Brassicaceous plants, including mustard (Brassica juncea) and camelina, as well as non-Brassicaceous plants, including jatropha, flax, and Chinese tallow, on Phymatotrichopsis omnivora sclerotial germination and hyphal growth in Branyon clay soil were investigated. The results showed that all tested brassicaceous and jatropha seed meals were able to inhibit P. omnivora sclerotial germination and hyphal growth at 5% and 1% application rates, respectively, with mustard seed meal being the most effective. All tested ITCs inhibited P. omnivora OKAlf8 hyphal growth, although the level of inhibition varied with concentration. Distinct bacterial and fungal communities occurred among amendment-type lines, with mustard inducing large increases in the abundance of the bacterial genera Bacillus, Pseudomonas, and Streptomyces spp., while other amendments increased Actinobacteria or Bacteroidetes abundances. Dramatic shifts were also seen among fungi, with fungal phylotype richness decreasing by > 60% following mustard seed meal addition. Loynachan (IA): Biochars impact on soil cultural practices and soilborne organisms and plant growth were examined. The percentage of carbon lost from the amendments after eight weeks was greatest for corn stover (44 wt%), followed by the two less completely pyrolyzedbiochars (9 and 10%), and least (4%) from the biochar made by fast pyrolysis at 500°C. Microbial availability roughly correlated inversely with the degree of pyrolysis completeness. There was an apparent shift in microbial communities from bacteria and actinomycetes to fungi with increasing pyrolysis. Broders (NH): Soil amendments and cover crops on disease suppression of Verticillium dahliae on strawberry and mint are being evaluated initially by screening strawberry accessions and a variety of cover crops for their ability to resist infection and suppress inoculum levels of the soilborne pathogen V. dahliae. Tillage systems impact was investigates as part of the project. Westphal (IN): Soybean under soybean monoculture in soil having no-tillage and infested with Fusarium virguliforme (causes sudden death syndrome; SDS) and soybean cyst nematode (Heterodera glycines) had less severe foliar symptoms of SDS in soil that had not been fumigated than in fumigated plots three years after pathogen infestation, suggesting that microbially-based soil suppressiveness had developed to these pathogens in the non-fumigated soil. Foliar symptoms of SDS in soybean were greater with chisel and moldboard plow tillage than with ridge tillage; yields were also improved with reduced tillage compared to intensive tillage. Padgett (LA): The impact of no-tillage, minimum tillage or conventional tillage on overwintering populations of several pathogens and diseases were examined. The incidence of Cercospora blight or purple seed stain on soybean did not differ among three tillage systems. Black root rot incidence on cotton was lower in conventional and minimum tillage systems. Rhizoctonia populations were highest in fields planted to grain sorghum and soybean; however, tillage practices did not impact Rhizoctonia populations. The microflora of several cropping systems were examined. Elliot (FL): Bermudagrass and bentgrass root microflora in sand-based putting greens were examined using fatty acid methyl ester profiles (GC-FAME). The two dominant genera in both bentgrass and bermudagrass rhizospheres were Bacillus and Pseudomonas, with Bacillus dominant in bermudagrass and Pseudomonas dominant or equal to Bacillus in bentgrass. Other genera that comprised at least 1% of the isolates at all four sites were Clavibacter, Flavobacterium and Microbacterium. Arthrobacter also comprised a significant portion of the bacterial isolates in the bentgrass rhizosphere, but not the bermudagrass rhizosphere. At the species level, there were five that comprised at least 1% of the isolates at each location; B. cereus, B. megaterium, C. michiganensis, F. johnsoniae and P. putida. Loynachan (IA): A large diversity of mycorrhizal fungi was documented in 8 soils of 4 soybean fields. Large variability exists within a single soil within a field. The composition of individual species varied within soil samples collected 3 m apart. Five species (Glomus. claroideum, G. etunicatum, G. mosseae, G. viscosum, and Paraglomus occultum) were detected in all samples collected. Baird (MS): Sweetpotato storage rots in Mississippi have increased dramatically causing substantial economic losses. Identification of root microorganisms of sweetpotato roots could support determination of a causal agent(s), or be used to systematically assess biologically based management. Microflora appear to shift in relative abundance between the growing cycle and harvest. Bacillus spp., L. enzymogenes, and P. lentimorbus accounted for more than 50% of bacteria identified. The majority of fungi were Macrophomina phaseolina, Aspergillus spp., Trichoderma spp., and a large number of Fusarium spp. In early season samples from seed stock and bedding plants, the community is primarily composed of Fusarium sp., nearly 70%. Post-harvest samples show differences in relative abundance of the dominant species, with M. phaseolina increasing to an average of 6.5% in samples taken from storage, and Fusarium spp. decreasing to an average of 27% between 60 and 90 days post-harvest. The impact of fertility, fungicides, and heavy metals were also being investigated by project scientists. Canaday (TN): Effects of chloride and ammonium salts on the incidence of Phytophthora root and stem rot of soybean were found to change the micro-partitioning of calcium in the soybean roots using energy-dispersive X-ray analysis. Use of sulfate of potash instead of muriate of potash increased plant stands by over 12% and increased snap bean yield by over 50%. Potash fertilizer form, fertilizer application timing, and seed treatment materials were evaluated for control of charcoal rot of soybean (caused by M. phaseolina) in both May-planted and June-planted field tests. Detectable levels of calcium in the outer cell layers of 10 to 13 day-old soybean taproots were significantly lower when plants were grown in soil treated with potassium chloride, sodium chloride, or magnesium chloride than when the plants were grown in untreated soil or soil treated with potassium sulfate. Fungicide hormesis was assessed in vitro on Pythium irregulare, Sclerotinia homoeocarpa, and Botrytis cinerea, validating the stimulation of pathogen activity by low fungicide levels. . It was demonstrated that sublethal doses of two fungicides, cyazofamid and propamocarb, as well as ethanol induce stimulation in Pythium aphanidermatum and that hormesis is involved in the stimulation processes. It was also demonstrated that low doses of ethanol induce stimulation in Rhizoctonia zeae and that hormesis is involved in the stimulation process, while propiconazole at sub-lethal doses do not have hormetic effects on either R. zeae or on R. solani. Loynachan (IA): Six heavy metals (Cd, Co, Cr, Cu, Ni, and Pb) reduced plant weights, nodulation, and N uptake on the legumes Vicia faba, Trifolium alexandrium, and Glycine max with increasing heavy metal concentrations, from 0 to as high as 4.3 mmol per kg soil. From the slopes of these lines, the concentrations of each metal required to produce 50% reduction in the parameter were calculated. Results showed that values varied among the soils and legumes studied but, in general, the lowest metal concentrations for 50% reduction (i.e., the most toxic) heavy metals were Cd and Pb. The value of cultivar resistance was examined on watermelon. Keineth (SC): The value of the rootstocks Emphasis, Macis (Lagenaria siceraria),Carnivor and Strong Tosa (Cucurbita moschata x Cucurbita maxima) for control of Fusarium wilt in watermelon were evaluated in a field experiment in South Carolina. The rootstocks were grafted with seedless watermelon Fascination (Citrullus lanatus var. lanatus), a new cultivar which is resistant to Fusarium oxysporum f. sp. niveum race 1 and susceptible to race 2. Plants were transplanted in a field known to be naturally infested with race 2 of Fusarium oxysporum f. sp. niveum. Wilt incidence was highest in the nongrafted and self-grafted Fascination with a mean of 81%. The four rootstocks had 2 to 16% wilted plants and did not differ from each other but differed from the control treatments. The four rootstocks also significantly increased the number of marketable-sized fruit compared to the control treatments. Objective 3. Examine the genetic diversity of Rhizoctonia solani between natural ecosystems and agricultural ecosystems. Committee members evaluated protocols for recovery of anastomosis groups (AG) of Rhizoctonia solani from soil using two techniques (soil pelleting and toothpick baits) and three media. M. Elliott found the poorest growth on water agar and best growth on Ko and Hora medium. B. Ownley also reported best results with Ko and Hora medium. C. Rothrock and A. Keinath reported that the ethanol-potassium nitrate medium was best. A. Keinath and K. Seebold reported that toothpick isolation was better than soil pellets. Keinath found that prochloraz slowed the growth of R. solani from soil and that rifampicin was a suitable substitute for tobramycin. Contamination was a problem with the Ko and Hora medium. Anastomosis groups detected were similar for the two selective media, two techniques, and seedlings. The toothpick method was an effective method for the recovery of R. solani from soils with diverse cropping histories because no special tools and few units were needed to detect the population. B. Ownley found the rates of damping-off were consistent with the population levels of R. solani detected in the three soils. Rhizoctonia solani was re-isolated from all damped-off broccoli seedlings. In Arkansas, the diversity of Rhizoctonia spp. in rice-soybean cropping systems included R. solani AGs 11, 1-1A, 4 and 2-1, Rhizoctonia oryzae and bi-nucleate Rhizoctonia species. Cubeta (NC): A field population of R. solani anastomosis group 3 (AG-3) consisting of 59 isolates was examined to determine the genetic diversity and evolutionary history of the genetic element M2 dsRNA This genetic element is hypothesized to be associated with altering the expression of metabolic pathways involved in parasitic and saprobic activity of the fungus. The distinct lineages and patterns of evolution inferred with coalescent analyses were unique for the M2 dsRNA genome. The M2 dsRNA genetic element was detected in representative isolates belonging to three anastomosis groups (AG) of R. solani (AG-1-IA, AG-4, and AG-6; teleomorph = Thanatephorus) and four AG of binucleate Rhizoctonia (AG-A, AG-F, AG-R, and AG-U; teleomorph = Ceratobasidium) using reverse-transcription polymerase chain reaction (PCR). Phylogenetic analysis of M2 dsRNA sequence data resulted in seven inferred haplotypes and there was no unique association with AG to support co-evolution of the M2 dsRNA haplotype within the fungal host. Based on the rooted gene genealogy inferred from coalescent analyses, the ancestral M2 dsRNA haplotype most likely evolved in R. solani AG-1-IA and has recently been acquired by isolates of Ceratobasidium. This is likely the first report of a dsRNA occurring in isolates of binucleate Rhizoctonia and other AG of R. solani. Horizontal transmission of the 3.57 kb M2 dsRNA between mycelia of somatically incompatible isolates of Rhizoctonia solani AG-3, an economically important pathogen of cultivated plants in the family Solanaceae, was investigated. The frequency of transmission observed between 72 pairings of the eight donor and three recipient isolates was approximately 4% of the total pairings and differences in the phenotype of the recipient isolates after acquisition of the M2 dsRNA via horizontal transmission were observed. Maintenance of the dsRNA in the recipient isolates was not stable following repeated sub-culturing on nutrient medium. Rothrock (AR):The spatial distribution of Rhizoctonia spp. in fields undergoing rice and soybean rotations is being characterized. Rhizoctonia aerial blight of soybean is a disease caused by Rhizoctonia solani AG1-IA. This pathogen also causes sheath blight of rice. Populations and disease assessments were characterized in producers field on a spatial scale by using a number of GPS positions to represent the topography of the field intermittent of the rice levee positions. Directional distribution ellipses for distribution of R. solani AG1-IA using soil and plant samples indicated agreement with drainage. Across years, distribution of R. solani AG1-IA appears to be controlled by levee position. Where levees do not form logical areas of collection, the greatest concentration of inoculum appears to be in the lower elevations of the field. Detection techniques were developed for Rhizoctonia and other pathogens Cubeta (NC) - The nuclear intergenic spacer (IGS) and a portion of the mitochondrial large subunit (mtLSU) ribosomal DNA (rDNA) genes from Sclerotinia minor and closely related species were amplified with PCR to develop specific primers. Both sets of primers did not amplify DNA of peanut (Arachis hypogaea), Botrytis cinerea, S. homeocarpa, S. sclerotiorum, and S. trifoliorum. Dick (OH): A biochemical assay was developed to detect Phytophthora sojae infestation in soil. The approach was based on profiling total cellular fatty acid methyl esters (FAME) of P. sojae in pure culture. A total of 12 fatty acids (14:0, 16:0, 18:0, 16:1 É7, 18:1 É9, 18:2 É6, 18:3 É6, 20:1 É9, 20:3 É6, 20:4 É6, 22:1 É9 and 24:1 É9) were identified in the FAME profiles of P. sojae (races 1, 4 and 7) pure cultures. The potential of using FAME profiles of P. sojae for detecting the pathogen in soil was evaluated by adding a known number of zoospores of P. sojae to soil. The results showed that fatty acids such as 18:1w9, 18:2w6, 20:1w9, 20:4w6 and 22:1w9 could be detected and quantified against the background levels of fatty acids present in soil. This outcome is significant because it offers the potential for a simple and rapid method for determining P. sojae infestations in soil. Borders (NH): The diversity of Rhizoctonia solani isolates associated with wheat, canola, soybean, and drybean by phylogenetic analysis. Garzon (OK): DNA fingerprinting protocols (AFLP, ISSR, SSR) were standardized for analysis of R. solani populations. Peanut populations of Sclerotinia from Oklahoma were characterized using AFLP and ISSR. Multiple strains of the Pythium irregulare species complex from diverse locations and hosts were characterized. Phylogenetic analyses of this clade showed evidence that multiple cryptic species exist. The genetic fingerprinting of multiple isolates of Phymatotrichopsis omnivora from Oklahoma, New Mexico, Texas and Arizona was completed. The genetic fingerprinting was completed and population genetic analyses performed of multiple isolates of Fusarium oxysporum f. sp. palmarum in collaboration with Monica Elliot, University of Florida.

Peer-reviewed Aliferis, K.A., Cubeta, M.A. and Jabaji, S. 2013. Chemotaxonomy of fungi in the Rhizoctonia solani species complex using GC/MS metabolic profiling. Metabolomics 9(Suppl.): 159-169. Bartz, F.E., Danehower, D.A., Glassbrook, N., and Cubeta, M.A. 2013. Modulation of the phenylacetic acid metabolic complex by quinic acid alters the disease-causing activity ofRhizoctoniasolanion tomato. Phytochemistry 89:47-52.. Bartz, F.E., Danehower, D.A., Glassbrook, N., and Cubeta, M.A. 2012. Elucidating the role of phenylacetic acid and hydroxy- and methoxy- phenylacetic acid derivatives in the pathogenic activity of Rhizoctonia solani AG-3. Mycologia 104:793-803. Burchhardt, K. and Cubeta, M.A. 2012. Microsatellite marker development for the plant pathogenic fungus Monilinia vaccinii-corymbosi. Molecular Ecology Resources 12:(In Press). Copes, W., Rodriguez-Carres, M., Toda, T., Rinehart, T.A., and Cubeta, M.A. 2011. Seasonal prevalence of species of binucleate Rhizoctonia fungi in growing medium, leaf litter, and stems of container grown azalea. Plant Dis. 95:705-711. Hansen, Z. R., and Keinath, A. P. 2013. Increased pepper yields following incorporation of biofumigation cover crops and the effects on soilborne pathogen populations and pepper diseases. Appl. Soil Ecol. 63: 6777. Kaye, A.C., Moyer, J.W., Parks, E.J., Carbone, I., and Cubeta, M.A. 2011. Population genetic analysis of Tomato spotted wilt virus on peanut in North Carolina and Virginia. Phytopathology 110:147-153. Keinath, A. P., Hassell, R. L., and DuBose, V. B. 2012. Field evaluation of six cucurbit rootstocks to manage Fusarium wilt on triploid watermelon, 2011. Plant Disease Management Reports 6:V024. doi: 10.1094/PDMR06. McCormick, M.A., Cubeta, M.A., and Grand, L.F. 2013. Geography and hosts of the wood decay fungi Fomes fasciatus and Fomes fomentarius in the United States. North American Fungi 8(2): 1-53. McCormick, M.A., Grand, L.F., Post, J.B., and Cubeta, M.A. 2013. Phylogenetic relatedness and phenotypic characterization of Fomes fasciatus and Fomes fomentariussampled from the United States. Mycologia 76: (Accepted). Richter, B. S., D. M. Benson, and K. L. Ivors, 2011. Microbial profiling of cultural systems for suppression of Phytophthora root rot in Fraser fir. Plant Dis. 95:537-546. Richter, B. S., Ivors, K. I., Shi, W., and Benson, D. M. 2011. Cellulase activity as a mechanism for suppression of Phytophthora root rot in mulches. Phytopathology 101:223-230. Samuels, G., Ismaiel, A., McMahon, P., Guest, D., Rosmana, A., Junaid, M., Rodriguez-Carres, M., and Cubeta, M.A. 2012. Vascular streak dieback of cacao in Southeast Asia and Melanesia: in planta detection of the pathogen and a new taxonomy. Fungal Biology 116(1):11-23. Thomas, E., Pakala, S., Fedorova, N. D., Nierman, W. C., and Cubeta, M. A. 2012.Triallelic SNP-mediated genotyping of regenerated protoplasts of the heterokaryotic fungus Rhizoctonia solani. Journal of Biotechnology 158:144-150. Toda, T., Strausbaugh, C., Rodriguez-Carres, M., and Cubeta, M.A. 2011.Characterization of a basidiomycete fungus from sugarbeet. Mycologia 104:70-78. Woodhall, J.W., Webb, K.M., Harper, G., Peters, J.C., Rodriguez-Carres, M., and Cubeta, M.A. 2011. First report of a new binucleate Rhizoctonia in UK potato tubers. New Disease Reports 23:31 [doi:10.5197/j.2044-0588.2011.023.031]. Yin, J., Koné, D., Rodriguez-Carres, M. Cubeta, M.A., Burpee, L.L., Fonash, E.G. Csinos, A.S., and Ji, P. 2011. First report of root rot caused by binucleate Rhizoctonia anastomosis group F on Musa spp. Plant Disease 94:490. Abstracts Hansen, Z. R., and Keinath, A. P. 2012. Increased pepper yields following incorporation of biofumigation cover crops and their effects on soilborne pathogen populations and pepper diseases. (Abstr.). Phytopathology 102:S4.49. Keinath, A. P., and Hassell, R. L. 2012. Grafting on hybrid squash and bottle gourd rootstocks to manage Fusarium wilt of watermelon. (Abstr.) Phytopathology 102:S4.153. Other publications Hansen, Z. R. 2011. Potential of three Brassica cover crops for biofumigation in the field and the relationship between soil myrosinase and biofumigation efficacy. Clemson University, M.S. Thesis. UMI Number 1505535 Loynachan, T. E. 2012. Life in the soil: Who cares? pp. 28-30. In Deborah McDonough (ed.) Getting Into Soil and Water. Iowa Water Center, Ames, IA. Seebold, K., 2012. Evaluation of a Biopesticide and Conventional Fungicides for Management of Phytophthora Blight of Yellow Squash. Pp. 32-34 in: 2011 Fruit and Vegetable Crops Research Report (PR-626). T. Coolong, J. Snyder, and C. Smigell, eds. UK Cooperative Extension Service, College of Agriculture, 53 pp Target Audiences This project was focused on evaluating commercial and non-commercial microbial biological control agents for control of soilborne plant pathogens, examining the effect of cultural practices on soilborne pathogens and plant growth, and examining the genetic diversity of Rhizoctonia solani between natural ecosystems and agroecosystems. Findings were shared with researchers and companies that provided the biological control agents for testing, and with collaborators of the Multistate Regional Research Project S-1028 in annual meetings. Highlights of this project were included in the S-1028 annual report, which was disseminated via the National Information Management and Support System (NIMSS) website. Findings were also shared with other scientists and students through research presentations at the American Phytopathological Society and other scientific meetings. Target audiences include producers of a variety of commodities, agricultural consultants, agricultural industry representatives, extension specialists, and other agricultural scientists interested in plant disease management. Producers/consultants use this information for decisions concerning disease management (product selection/cultural practices) in row crops.