Brief Summary of Minutes of Annual Meeting

Doug Jardine called the meeting to order and asked participants to introduce themselves. The Director of the Western Tenn Research and Extension Center then welcomed the group to the station. Steven Slack reviewed administrative details including reporting requirments and encouraged members to make sure they contact their experiment station director to document membership and participation in the committee. The group then transitioned to state reports. (See summaries below) Business Meeting: (March 8) Doug reviews the duties of chair and secretary for the committee. He notes that Erick De Wolf will finish his term as secretary after this meeting and become the Chair for 2007. He then asked for nominations of volunteers for the secretary in 2007/Chair in 2008. Laura Sweets was nominated and after some discussion agreed to serve. The committee then approved her nomination and elected her by unanimous vote. The next meeting is to be held in conjunction with the soybean breeders meeting. This meeting is typically held the 2nd week of Feb. in Saint Louis, MO. Erick will work with them to develop a program. Suggested topics include: The Diseases breeders are interested in, and opportunity to present cooperative projects from different groups including: Charcoal rot, frog eye leaf spot, Phytophthora, Soybean Rust, Sudden Death Syndrome, Viruses Report summaries: Nebraska: In 2005, Nebraska soybean producers harvested 4.7 M acres of soybean with an average yield of 50.5 bu/A (increase of 4.0 bu./A over 2004 and 2004 was increased 6.5 bu./A over 2003). In fields that planting occurred prior to spring rains, we did see some seeding disease activity caused by Pythium spp. and Phytophthora in the eastern third of Nebraska. Our most commons seedling disease problem in the diagnostic clinic this year was Rhizoctoinia. Foliar diseases observed in soybean rust sentinel plots and Nebraska Crop Surveillance Network (NCSN) fields were Bacterial Blight, Bacterial Pustule, and Brown Spot. Very little Downey Mildew was observed in 2005. A sampling project funded by the Nebraska Soybean Board in 2005 resulted in the detection of SCN further west in Nebraska, several with very high SCN populations. In 2005, sudden death syndrome was confirmed in several more fields across the eastern third of the state and all locations were the earliest fields planted in the area. Occurrence of Bean pod mottle virus (BPMV) was greater in 2005 than in 2004 and bean leaf beetle populations were higher than the previous year. Current research projects relating to soybean pathology include studies on strobilurin fungicide effects on yield, chemigation as a means of applying fungicides to soybean, influence of variety genetics on Phytophthora management, and yield impact assessment for BPMV. Wisconsin: Soybean diseases of most economic importance are soybean cyst nematode, brown stem rot, Phytophthora root rot and Sclerotinia stem rot. Soybean cyst nematode has expanded to 41 of 72 counties, which represents 90% of the soybean acreage in Wisconsin. Aphid transmitted viruses remain at low incidence in commercial fields despite soybean aphid activity in past years. Soybean dwarf virus (SbDV) was detected in soybean and red clover, but at a low incidence in soybean. Research continued on phenotypic and genotypic characterization of resistance to Phialophora gregata, Sclerotinia sclerotiorum, Bean pod mottle virus, and Alfalfa mosaic virus. Significantly higher levels of resistance were identified for Phialophora gregata, Sclerotinia sclerotiorum, and Alfalfa mosaic virus. Symptom severity and pathogen reproduction were both employed to characterize interaction phenotypes of soybean lines in greenhouse and field trials. Diaporthe phaseolorum var. meridionalis, D. phaseolorum var. caulivora and D. phaseolorum var. sojae were isolated from soybean stems at growth stage R8. Research has focused on etiology and methods to identify each form of D. phaseolorum. Fungicides were evaluated at four locations and yield improvement averaged 1.5 bu/a, with a high of 6.5 bu/a acre at one location. An R2 application of Headline resulted in a 6 bu/a yield improvement for a brown stem rot susceptible soybean variety. Yield was not improved for a brown stem rot resistant soybean cultivar. Kansas: Soybean production for Kansas in 2005 was 105.5 million bushels, down by 5% from 2004. Estimated losses from disease were 5.75% with seedling diseases, brown spot, anthracnose, brown spot, Phytophthora root rot and SCN being responsible for the bulk of the losses. Fungicide spray trials were conducted at three locations, with the end result being that, in the absence of soybean rust, economic loss would have occurred at two of three locations. While soybean cyst nematode continues to spread across the state, yield losses have not noticeably increased due to improved yield potential of resistant varieties in the Group 3 varieties and more varieties available with stacked traits that include SCN resistance. Kansas continues to publish female indices values for all varieties in the Kansas Soybean Performance Test. The incidence of virus infected soybeans was up for the second consecutive year. Tobacco ringspot and bean pod mottle virus were most often identified. Ohio: A cold, wet spring led to some stand establishment issues in Northwest and south central Ohio with snow covering many fields during the last two weeks of April. SCN could be found in many areas of the state, the size of the high infestations (stunting) continues to grow. Some recent counts from the diagnostic clinic have reached 50,000 to 90,000 per cup of soil. Sclerotinia was spotty at best. Few reports of SDS and brown stem rot. Research Projects and Progress discussed included: Mapping Rps8 resistance to Phytophthora sojae; Characterizing the resistance to P. sojae in PIs from South Korea; Components of partial resistance in roots of soybean; Cytological comparison of partial resistance, Rps2, root resistance and R-gene response to Phytophthora sojae; Characterizing seedling pathogens from problem fields in Ohio; and Evaluation of Quadris/Warrior applications for yield benefits. Pennsylvania: Growing conditions in PA where near slightly below normal during the 2005 growing season. Dry weather prevailed during the early part of the growing season, and some producers struggled with delayed germination and seedling emergence. Sporadic rains in May and early June keep the crop growing but canopy closure was delayed in some areas of the state. Foliar diseases remained at low levels in most fields with Septoria brown spot being the most commonly reported disease. As summer progressed frog-eye leaf spot and downy mildew were commonly reported. Based on a samples received by either Dr. De Wolf or the Plant Disease Diagnostic Lab, frog eye leaf spot may have been damaging levels in a small number of fields. Dry conditions appeared to hasten the maturation of the soybean crop in most areas of the state, and yields were near the state average. Soybean disease research at Penn State University focused on white mold (Sclerotinia stem rot), Soybean rust and fungicide evaluation during the 2005 growing season. Ontario: Soybean growers faced numerous production challenges in 2005 including soybean cyst nematode, aphids, spider mites, phomopsis, bean leaf beetles, and adverse weather. Geography played a large part in how much this impacted individual producers. A lack of moisture was a problem for many areas while some parts of eastern Ontario suffered from excess rainfall. Despite these difficulties, yields were generally at or above average. The range reported was from a low of 25 to a high of 75 bu/ac. The provincial was approximately 41 bu/ac. Over 2.35 million acres of soybeans were planted in 2005, making soybeans the largest row crop in Ontario. A dry spring across much of the province allowed most soybeans to be planted under good conditions and during the ideal planting window. Many producers were able to complete soybean seeding by May 25th. In some counties, fields were so dry that soybean emergence was poor resulting in some replanting being required. Research topics included: evaluation of control strategies for Phytophthora root rot. Indiana: Disease losses caused by Phytophthora root rot, sudden death syndrome (SDS), brown stem rot, and soybean cyst nematode (SCN) continued to be important in Indiana in 2005. New awareness of Rps8 virulence by isolates of several P. sojae races suggest it is important to continue evaluating P. sojae inoculum potential in soybean fields to determine just how to develop future control strategies. Dr. Dorrance and several of the NC plant pathologists are currently working on this problem as a NCSRP activity. I am presenting information about my Rps8 data during one of the SSDW sessions. Awareness of Frogeye leaf spot caused by Cercospora sojina was definitely increased. Scouting due to the ASBR potential enhanced some of the FE awareness; FE frequency and severity were such that it emphasizes the need for breeders to give more attention to including the Rcs3 resistant gene in new cultivars. Soybeans with the Rcs3 gene that were inoculated in 2004 and 2005 tests were resistant to all isolates of C. sojina that Abney has collected from central and southern IN during the past three years. Several IN soybean producers were insistent that FE caused excessive yield losses; however Greg Shaner and I were not able to document the nature of infection and/or defoliation at any of the field locations in question. Minnesota: soybean growers harvested 299 million bushels of soybeans from 6.8 million acres in 2005. Average yields were 44.5 bushels per acre, which was a record. This is in contrast to 233 million bushels of soybeans harvested from 7.05 million acres in 2004. Most planting was delayed by extremely wet and cold conditions statewide during May. However, temperature and moisture conditions during June, July, and August were optimal for crop growth and yield. Because of the coincidence of ideal growing conditions with planting seedling roots were only a minor problem. The principle cause of seedling diseases was Fusarium spp. Only two reports of stand loss to Phytophthora sojae were received in the Plant Disease Clinic. Race 25 was isolated from samples collected in the affected fields. A network of sampling sites was established to detect spores of Phakopsora pachyrhizi. Beginning in late July and into August P. pachyrhizi spores were detected on 10 weekly sample dates in rainfall collectors located in these sites. Research topics included: SBR Sentinel Plots; Modeling and Trajectory Analysis for SBR; SBR Forecaster; Pathotypes of Phytophthora sojae present in fields showing symptoms of Phytophthora root rots; Foliar Fungicide Applications; and Breeding Efforts. Missouri: The 2005 season was an interesting one for soybean production in Missouri. Just under five million acres of soybean were harvested with an average yield of 37 bushels per acre. This is eight bushels down from the record 2004 yield of 46 bushels per acre. Weather conditions were a major contributing factor during the 2005 season. Most of the state had extremely dry conditions for June, July and the first week of August. The remainder of August was unusually wet. September to date have again been on the dry side. Temperatures were normal to slightly below normal for most of the season. Drought took its toll on yields in some areas of the state and in some early planted fields. The August rains were crucial saving the crop for much of the state. North Dakota: The soybean acreage in North Dakota is now around 4 million acres and is expected to increase with soybean production moving north and west. The soybean disease research projects in 2005 were: 1) identification of virulence phenotypes of Phytophthora sojae and characterization of sensitivity to metalaxyl, 2) biology of Fusarium root rot, 3) identification of sources of partial resistance to P. sojae in northern germplasm, 4) biology of SCN in North Dakota, 5) incorporation of resistance to P. sojae and soybean cyst nematode (SCN) into public soybean cultivars (cooperative study with breeder), 6) evaluate efficacy of seed treatment and foliar fungicides on soybean, and 7) monitor for Asian soybean rust using a sentinel plot network. Research topics included: Phytophthora root rot; Biology of Fusarium root rot; Soybean Cyst Nematode; Fungicide Efficacy Trials and Asian Soybean Rust Monitoring.

Identification of new soybean diseases and distribution changes for disease causing species and biotypes helps soybean producers effectively manage disease problems and assists companies in positioning soybean varieties in local markets. Research evaluating the affects of currently marketed fungicides for foliar and seed protection provides the data necessary to assist soybean producers in making treatment decisions. The combined efforts of researchers involved in this committee result in the soybean disease management recommendations developed by all states. The coordination of efforts and reports with the committee greatly assist in development of a uniform recommendation for management.

Bolton, M. D., Nelson, B. D., Sparks, R. B., and Santoso, A. 2005. Methods for Extraction and Amplification of DNA from Soybean Seed. Seed Technology 27:89-94. Bradley, C. A., Hartman, G. L., Mueller, D. S., Hoffman, D. D., Nickell, C. D., and Pedersen, W. L. 2005. Genetic analysis of partial resistance to Rhizoctonia solani in the soybean cultivar Savoy. Can. J. Plant Pathol. 27:137-142. Bradley, C. A., Chesrown, C. D., and Helms, T. C. 2005. Evaluation of seed treatments for effect on stand, root disease, and yield of soybean in North Dakota, 2004. F&N Tests 60:ST018. Bradley, K. W., L. E. Sweets, J. Li, and J. D. Wait. 2005. Influence of glyphosate-fungicide combinations on weed control, spray penetration, and yield in glyphosate resistant soybean. Weed Sci. Soc. Amer. Abstr. 45: 6-7. da Rocha, M. R., AndersonT. R., and T. Welacky. 2005. Effect of harvest timing on Heterodera glycines race and HG type characterization. Nematologia Brasileira. 28: 167-171 De Silva, A, Bolton, M., and Nelson, B. 1995. Transformation of Sclerotinia sclerotiorum with the green fluorescent protein gene and expression of fluorescence in host tissues. Phytopathology 95: S23 Dorrance, A.E., Draper, M.A. and Hershman, D.E. (Editors) 2005. Using Foliar Fungicides to Manage Soybean Rust. OSU Extension Bulletin SR-2005. 51pp. Chaudhary, S., Anderson, T. R., Park, S.J. and K. Yu. 2006. Comparison of screening methods for resistance to Fusarium root rot in common beans (Phaseolus vulgaris L.). Plant Pathology: (in press) Chen, S.Y., Kurle, J.E., Stetina, S., Miller, D., Nelson, G., Klossner, L.D., Hansen, N. Interactions Among Iron deficiency Chlorosis, Soybean Cyst Nematode, and Root Rot in Minnesota Soybean Fields. (Submitted to Agronomy Journal). Giesler, L.J. and Ziems, A.D. 2006. Incidence of Alfalfa mosaic virus, Bean pod mottle virus and Soybean mosaic virus in Nebraska soybean fields. Plant Health Progress doi 10.xxx . (In Press) Giesler, L.J., Wilson, J.A. and Rees, J.M. 2005. Soybean Rust Fungicide Use Guidelines for Nebraska. NF05-652. University of Nebraska-Lincoln Extension. Giesler, L.J. and Weissling, T.J. 2005. Fungicides to Manage Soybean Rust: What are the Product Differences? NF05-634. University of Nebraska-Lincoln Extension. Giesler, L.J. 2005. Soybean Rust: How Great is the Threat for Nebraska? NF05-633. University of Nebraska-Lincoln Extension. Giesler, L.J. and A.D. Ziems. 2005. Effect of seed treatment fungicides on soybean stand, vigor and yield, 2004. Fungicide and Nematicide Tests 60:ST017. Giesler, L.J., Watson, S.R.and Weissling, T.J. 2005. Effects of foliar fungicide and Insecticide combinations on soybean aphid, brown spot and plant development, 2004. Fungicide and Nematicide Tests 60:FC140. Gordon, S.G., St.Martin, S.K., and Dorrance, A.E. 2006. Rps8 Maps to a resistance gene rich region on soybean molecular linkage group F. Crop Sci. 46:168-173. Graham, MY. 2005. The diphenylether herbicide lactofen induces cell death and expression of defense-related genes in soybean. Plant Physiology 139:1784-94 Helms, T.C., B.D. Nelson and R.J. Goos. 2005. Registration of LaMoure Soybean. Crop Sci. 45:410 Sweets, Laura E., J. Allen Wrather and Simeon Wright. 2004. Soybean Rust. MU Guide G4422, University of Missouri Extension. 6 pages. Jardine, D. J., B. Gordon, L. Maddux, J.H. Long. 2005. Effects of seed treatment fungicides on stand and yield of soybean, 2004. F&N Tests 60:ST005. Khan, F. U., Nelson, B. D., and T. C. Helms. 2005. Greenhouse evaluation of binucleate Rhizoctonia for control of R. solani on soybean. Plant Dis. 89:373-379. Koch, K., D. Ragsdale, B. Potter, and J. Kurle. Suppression of Entomopathogens of Soybean Aphid by Foliar Fungicides. National Soybean Rust Symposium. Sponsored by the American Phytopathological Society. Nashville, TN. 14-16 Nov. 2005. (http://www.plantmanagementnetwork.org/infocenter/topic/soybeanrust/symposium/posters/44.asp) Kurle, J. , V. Bowersox, R. Claybrooke, S.V. Krupa, C. Barnes, and L. Szabo. 2005: Introduction and spread of soybean rust spores in the North Central United States. National Soybean Rust Symposium. Sponsored by the American Phytopathological Society. Nashville, TN. 14-16 Nov. 2005. (http://www.plantmanagementnetwork.org/infocenter/topic/soybeanrust/symposium/posters/19.asp) Lee-Burrows, M.E., Boerboom, C.M., Gaska, J.M., and Grau, C.R. 2005. The relationship between Aphis glycines and Soybean mosaic virus incidence in different pest management systems. Plant Dis. 89:926-934. McSpadden Gardener, B., Gutierrez, L., Joshi, R., Edema, R., and Lutton, E. 2005. Distribution and biocontrol potential of phlD+ pseudomonads in corn and soybean fields. Phytopathology 95:715-724. McSpadden Gardener, B., C. Kroon van Diest, and J. Beuerlein 2006. Evaluation of biological seed treatments containing phlD+ strains of Pseudomonas fluorescens on soybeans grown in Ohio, 2005. Meng, X., C.R. Grau, and W. Chen. 2005. Two sympatric and genetically distinct populations of the fungal pathogen Phialophora gregagta f.sp. sojae show differential cultivar preference. Plant Pathology 54:180-188. Mueller, T. A., Bradley, C. A., Chesrown, C. D., Walker, E. R., Koger, C. H., Morel, W., Miles, M. R., and Hartman, G. L. 2005. Response of soybean to timing of fungicide applications in the presence and absence of Phakopsora pachyrhizi. Proceedings of the National Soybean Rust Symposium, Nashville, TN. Online at: http://www.plantmanagementnetwork.org/infocenter/topic/soybeanrust/symposium/ Nelson, B., and Mallik, I. 2005. Pathotypes and metalaxyl sensitivity of Phytophthora sojae from North Dakota soybean fields. Phytopathology 95: S74. Nelson, B. D., and Danielson, G. 2005. Soybean virus survey in North Dakota. Phytopathology 95: S164-165. Nelson, B. 2005. Characterization of infection of two soybean genotypes by Sclerotinia sclerotiorum. Phytopathology 95: S164. Patzoldt, M.E., Grau, C.R., Stephens, P.A., Kurtzweil, N.C., Carlson, S.R., and Diers, D.W. 2005. Localization of a quantitative trait locus providing brown stem rot resistance in the soybean cultivar Bell. Crop Sci. 45:1241-1248. Rabedeaux, P.F., J.M. Gaska, N.C. Kurtzweil, and C.R. Grau. 2005. Seasonal progression and agronomic impact of Tobacco streak virus on soybean in Wisconsin. Plant Dis. 89:391-396. Subramanian, S., M. Y. Graham, O. Yu, and T.L. Graham 2005. RNA Interference of Soybean Isoflavone Synthase Genes Leads to Silencing in Tissues Distal to the Transformation Site and to Enhanced Susceptibility to Phytophthora sojae. Plant Physiol. 137: 1345-1353 Vega-Sánchez, M.E., Redinbaugh, M.G., Costanzo, S., and Dorrance, A.E. 2005. Spatial and temporal expression analysis of defense-related genes in soybean cultivars with different levels of partial resistance to Phytophthora sojae. Physiol. and Molec. Plant Pathology 66:175-182. Werk, W. 2005. Partial resistance to Phytophthora root rot in soybean and association with tolerance to saturated soil conditions. Masters Thesis, Plant Science Dept. North Dakota State University. Fargo, ND Zhao, G. G. R. Ablett, T. R. Anderson, I. Rajcan, and A.W. Schaafsma. 2005. Anastomosis groups of Rhizoctonia solani associated with soybean root and hypocotyl rot in Ontario and resistance of accession PI 442031 to different anastomosis groups. Can J. Plant Path. 27:1-10. Zhao, G., Ablett, G. R., Anderson,T. R., Rajcan, I. and A. W. Schaafsma. 2005. Inheritance and genetic mapping of resistance to rhizoctonia root and hypocotyl rot in soybean. Crop Sci. 45:1441-1447. Ziems, A.D. and Giesler, L.J. 2006. First report of Sudden Death Syndrome (Fusarium solani f.sp. glycines) of Soybean in Nebraska. Plant Dis. 90:109.