Progress 09/15/05 to 09/14/08
Outputs
OUTPUTS: Fortunately for the major organic soybean producing areas of the U.S., Asian soybean rust (ASR) did not reach an epidemic stage during the course of the project (2005 to 2008), despite isolated findings in Iowa in 2007 and other states outside of this project's scope. As of December 2008, ASR was reported in 396 counties in the U.S. Research supported by this project in Florida, where ASR has been occurring since 2004, led to the identification of viable strategies, including NOP-compliant copper-based fungicides, for effectively managing ASR in organic systems and mitigating losses in the event of severe infection. In addition, the application of natural silicon was investigated and found to delay ASR disease onset in Florida. Other successful pest management strategies included trap crops to prevent stink bugs from colonizing organic soybeans. In areas where ASR has not yet arrived, methods of improving organic soybean systems, including reduced tillage and varietal selection to mitigate other soybean diseases, resulted in greater maintenance of soil quality and higher returns for farmers. Over the three years of the project, dissemination of information to over 1,200 people has occurred through presentations at annual Field Days held in each state, and at the Iowa Organic Conference, Michigan Sustainable Farming Association Conference and the Upper Midwest Organic Farming Conference each year. On-line reports have been posted at the following sites: NewFarm, New Ag Network, OrganicAgInfo and each institutions' research farm and individual organic websites, including http://extension.agron.iastate.edu/organicag/. Through these efforts, we have increased the knowledge base and skills of thousands of organic farmers across the U.S. in Asian soybean rust diagnostic and management tools. Activities supported through this project in 2008 included the establishment of four research experiments in Florida, Iowa, Michigan and Pennsylvania; analyzing all data from sites; four state reports and one overall project report; three Field Days in Michigan, Iowa, and Pennsylvania; and the Florida site serving as a demonstration site for ag professionals receiving training in ASR. Products produced included new applied knowledge and technology for ASR management in organic systems, and the sharing of this information on websites listed below. A hands-on training of the latest technology for ASR detection, an ELISA strip test (EnviroLogix, Portland, Maine) was demonstrated to 68 producers and Extension personnel in Iowa on September 23, 2008. PARTICIPANTS: Participants in this project include Jerry DeWitt and Robert Turnbull (Iowa State University), Ann Blount, David Wright, Cheryl Mackowiak, Jim Marois, Richard Sprenkel, Steve Olson and Russell Mizell (University of Florida), Dale Mutch, George Bird and Mark Whalon (Michigan State University), and Jeff Moyer and Paul Hepperly, The Rodale Institute. Partner organizations include the Iowa Organic Association, Michigan Sustainable Farmers Association and the many outreach agencies through The Rodale Institute's efforts. Professional development opportunities for Extension and farmers from this project have included participation in Field Days and conferences described above. TARGET AUDIENCES: Target audiences have been organic soybean growers in the U.S. and in the world. Organic and non-GMO soybean processors are also interested in these results. Efforts include Extension-based dissemination, such as Field Days, conferences and on-line reports. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Asian soybean rust (Phakopsora pachyrihizi) (ASR), arrived in the U.S. in 2004 and ranged to Canada in 2008. Because there was no organic-compliant control of ASR the purpose of this project was to evaluate tools, including organic-compliant fungicides and cultural strategies to limit damage from ASR. On-station organic fungicide efficacy studies in Florida, where rust has been extremely active and in Iowa, Michigan and Pennsylvania for their effect on yields and other soybean diseases were conducted. In Florida, an organic trial was established in 2005 to examine the effects of organic-compliant fungicides on ASR on soybeans grown on land in transition to certified organic status. Over all years, the most effective fungicides were copper hydroxide and copper sulfate when plants were rated according to the Horsfall-Barrett rating scale (0 = 0%; 11 = 100% diseased). At the highest disease rating period in 2006, soybean plants treated with Champion (copper hydroxide) and basic copper sulfate were rated 2.0 and 2.6, respectively, compared to the control at 7.4. In 2007, copper-treated plants averaged 2.6 compared to the control at 4.8. Yields were greater in these treatments in 2006 and 2007. There were few differences detected between the control and Bacillus pumilis, capryllic acid, Hoshizaki water, hydrogen dioxide, and microbial combinations (AN and MAF). These results suggest promise for copper-based products for organic management of ASR, but build-up in routine use of copper fungicides must be considered. Across all years, data have shown that in Iowa, Pennsylvania and Michigan, no significant differences in organic soybean yields were found in soybeans treated with Bacillus pumilis, an OMRI-listed fungicide that has shown some efficacy against ASR in South Africa. Other ASR fungicide products that were tested in this project showed no effects on yields or soybean diseases, although soybean oil in Pennsylvania caused some phytotoxicity in organic soybeans in 2007. Organic soybean yields were excellent in 2008 (averaging 53 bu/acre), despite significant flooding in Iowa in 2008. Diseases were low, despite long periods of flooding. Across all years, yields ranged from13 bu/acre in a severe drought year in Michigan in 2007 to 65 bu/acre in Iowa the same year. Later planting, a possible strategy for ASR management, led to equivalent yields if planting occurred before June 16. No significant differences in mite or natural enemy diversity, or nematode community structure were detected among the fungicide treatment or planting dates, but the population densities of bacterivores in organic plots were generally higher than those associated with conventional soybean production sites in Michigan. Another potential strategy, planting soybeans into a rolled cover crop, was evaluated for yield and disease effects. Across all years, the highest organic soybean yield occurred in Iowa in 2007, when yields averaged 45 bu/acre in a rolled cover crop of hairy vetch/rye with no rust detected and other soybean diseases ranging from 0 to 2.3% of leaves infected. As a result of this effort soybean producers now have an effective tool with which to counter ASR.
Publications
- Gevens, A.J., D.L. Wright, A. Blount, R.F. Mizell, R.K. Sprenkel, C. Mackowiak, S.M. Olson, J.A. Smith, J.J. Marois, and L.E.Datnoff. 2007. Using foliar fungicides to manage soybean rust (Alternatives for organic soybean production). On-line at: NCERA-208. http://oardc.osu.edu/soyrust/
- Delate, K. 2008. Evaluation of Organic Soybean Rust Treatments for Organic Production. Neely Kinyon Trial 2008. Iowa State University Experiment Station Reports Ames, IA.
- Delate, K., A. Blount, C. Mackowiak, D. Wright, and R. Turnbull. 2008. Efficacy of organic-compliant fungicides for Asian soybean rust. Proc. National Soybean Rust Symposium, Louisville, KY, December 12-14, 2007. On-line at: http://www.plantmanagementnetwork.org/infocenter/topic/soybeanrust/20 07/posters/49.asp.
- DeWitt, J., R. Turnbull, A. Blount, C. Mackowiak, and D. Wright. 2008. Evaluation of organic-compliant fungicides for ASR in organic soybean production. USDA National SARE Conference, March 25-27, 2008, Kansas City, MO.
- Lemes, E., C. Mackowiak, L. Datnoff, J. Marois, and A. Blount. 2008. Effects of soil and foliar applied silicon on Asian soybean rust (Phakopsora pachyrhizi) development in organic production systems. European Network for Durable Exploitation of Crop Protection Strategies, Oct. 12-15, La Grande Motte, France.
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Progress 09/15/06 to 09/14/07
Outputs
OUTPUTS: This research has identified potential strategies, such as copper-based fungicides, for effectively managing ASR in organic systems and mitigating losses in the event of severe infection. In areas where ASR has not yet arrived, methods of improving organic soybean systems, including reduced tillage and varietal selection for other soybean diseases, can result in greater maintenance of soil quality and higher returns for farmers. Dissemination of information to over 600 people has occurred through presentations at Field Days and the Iowa Organic Conference, Michigan Sustainable Farming Association Conference and the Upper Midwest Organic Farming Conference. On-line reports have been posted at the following sites: NewFarm, New Ag Network, OrganicAgInfo and each institutions' research farm and individual organic websites, including http://extension.agron.iastate.edu/organicag/. Through these efforts, we have increased the knowledge base and skills of thousands of organic
farmers across the U.S. in Asian soybean rust diagnostic and management tools. Activities supported through this project in 2007 included the establishment of four research experiments in Florida, Iowa, Michigan and Pennsylvania; analyzing all data from sites; four state reports and one overall project report; three Field Days in Michigan, Iowa, and Pennsylvania; the Florida site serving as a demonstration site for over 50 people who received training in ASR; and individual consulting with three organic soybean companies regarding ASR management. Products produced included new applied knowledge and technology for ASR management in organic systems, and the sharing of this information on websites listed below.
PARTICIPANTS: Participants in this project include Dr. Jerry DeWitt and Robert Turnbull (Iowa State University), Ann Blount, David Wright, Cheryl Mackowiak, Jim Marois, Richard Sprenkel, Steve Olson and Russell Mizell (University of Florida), Dale Mutch, George Bird and Mark Whalon (Michigan State University), and Jeff Moyer and Paul Hepperly, The Rodale Institute. Partner organizations include the Iowa Organic Association, Michigan Sustainable Farmers Association and the many outreach agencies through The Rodale Institute's efforts. Professional development opportunities for Extension and farmers from this project have included participation in Field Days and conferences described above.
TARGET AUDIENCES: Target audiences have been organic soybean growers in the U.S. and in the world. Organic and non-GMO soybean processors are also interested in these results. Efforts include Extension-based dissemination, such as Field Days, conferences and on-line reports.
PROJECT MODIFICATIONS: None
Impacts
Asian soybean rust (Phakopsora pachyrihizi) (ASR), arrived in the U.S. in 2004, continues to spread across the U.S., affecting more regions in 2007 than at any other time and has the potential for being the most important impediment to organic soybean production. As of December 2007, ASR has ranged as far north as Canada and Iowa, although the disease appeared late in the season and did not affect yields. At the initiation of this research, there was no organic-compliant control of ASR. The purpose of this project is to evaluate tools, including organic-compliant fungicides and cultural strategies to limit damage. Our objectives include on-station studies and on-farm surveys conducted in Florida, where rust has been extremely active and testing organic fungicides in Iowa, Michigan and Pennsylvania for their effect on yields and other soybean diseases. Pennsylvania and Michigan missed ASR in 2007, and no ASR was found in organic soybean trials in Iowa, probably due to
exceptionally dry weather in the Southeast during the early soybean-growing season. In Florida, an organic trial was established in 2005 to examine effects of organic-compliant fungicides on ASR on soybeans grown on land in transition to certified organic status. Fungicides were tested in 2007 and plants rated according to the Horsfall-Barrett rating scale (0 = 0%; 11 = 100% diseased). Plants treated with copper hydroxide and copper sulfate exhibited the lowest rates of disease, with no differences detected between the control and Bacillus pumilis, capryllic acid, Hoshizaki water, hydrogen dioxide, and microbial combinations (AN and MAF). These results suggest promise for copper-based products for organic management of ASR, but issues associated with extended copper use must be considered. Research to date has shown that in Iowa, Pennsylvania and Michigan, no significant differences in organic soybean yields were found in soybeans treated with Bacillus pumilis, an OMRI-listed
fungicide that has shown some efficacy against ASR in South Africa. Other ASR fungicide products tested in Pennsylvania (soybean oil) caused some phytotoxicity in organic soybeans. Organic soybean yields were excellent in 2007 in Iowa and Pennsylvania with no differences between three varieties tested. Due to severe drought in Michigan, yields only reached 13 bu/acre. No significant differences in yields were detected when soybeans were planted earlier (May 22) versus later (June 16), a possible strategy for ASR management. No significant differences in mite or natural enemy diversity, or nematode community structure were detected among the fungicide treatment or planting dates, but the population densities of bacterivores in organic plots were generally higher than those associated with conventional soybean production sites in Michigan. Another potential strategy, planting soybeans into a rolled cover crop, was evaluated for yield and disease effects. In Iowa, in 2007, yields
averaged 45 bu/acre in a rolled cover crop of hairy vetch/rye with no rust detected and other soybean diseases ranging from 0 to 2.3% of leaves infected.
Publications
- Delate, K. 2007. Evaluation of Organic Soybean Rust Treatments for Organic Production. Neely-Kinyon Trial. 2007. Iowa State University Experiment Station Reports, Ames, IA: http://www.ag.iastate.edu/farms/06reports/arm/EvalOrganicSoybean.pdf
- Grossman, J. 2007. ESA 2006 Annual Meeting Highlights 3rd Part: Organic Soy Fungicides. The IPM Practitioner: Monitoring the Field of Pest Management 29 (5/6):14.
- Hepperly, P. 2007. Old Asian Soybean Rust research from many places holds valuable natural defense clues. The Rodale Institute New Farm on-line journal: http://www.newfarm.org/columns/research_paul/2007/0407/soybeanrust.sh tml
- Johnson, A.m., M. E. Whalon, D. R. Norton, W. W. Byran. 2006. Effect of organic fungicides on natural enemies in Michigan soybean production. Proceedings of the 2006 Annual Meeting of the Entomological Society of America. Abstr. D 0038.
- Bird, G. W. 2007. Correction: Asian Soybean Rust not found in Michigan in 2007. The IPM Practitioner: Monitoring the Field of Pest Management 29 (7/8):9.
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Progress 09/15/05 to 09/15/06
Outputs
Asian soybean rust (Phakopsora pachyrihizi) (ASR), which arrived in the U.S. in 2004, has the potential to be the single most important impediment to organic soybean production in the U.S. As of December 2006, ASR has ranged as far north as Indiana and Illinois. At the initiation of this research, there was no known organic-compliant control of ASR, thus the purpose of this project is to evaluate tools, including organic-compliant fungicides and cultural strategies, such as extended crop rotations and windbreaks to mitigate spore dispersal. Our objectives include on-station studies and on-farm surveys conducted in Florida, where rust has been discovered, and in Iowa, Michigan and Pennsylvania. The Upper Midwest and Pennsylvania missed ASR in 2006, probably due to exceptionally dry weather in the Southeast during the early soybean-growing season. In Florida an organic trial was established in 2005 to examine effects of organic-compliant fungicides on ASR on soybeans
grown on land in transition to certified organic status. The fungicides tested in 2006 and the resulting ASR disease severity ratings, according to the Horsfall-Baratt rating scale (0 = 0%; 11 = 100% diseased) were as follows: Control (untreated)-7; copper hydroxide-2; copper sulfate-2; Bacillus pumilis-3-4 (early); 5-6 (later in season); capryllic acid-4-5; Hoshizaki water-5; hydrogen dioxide-5; microbial combination (AN)-6; and microbial combination (MAF)-6. These results suggest promise for copper-based products for organic management of ASR. The issues associated with extended copper use, however, must be considered. Research to date through this project has shown that in Iowa, Pennsylvania and Michigan, no significant differences in organic soybean yields were found in soybeans treated with Bacillus pumilis, an OMRI-listed fungicide that has shown some efficacy against ASR in South Africa. However, plants treated with Bacillus pumilis were taller and deeper green at harvest, with
a delayed senescence in Pennsylvania. Other ASR fungicide products tested in Pennsylvania (lime-sulfur and soybean oil) caused some phytotoxicity in organic soybeans. Organic soybean yields were excellent in 2006, despite extensive drought conditions in Iowa in June and July. Yields ranged from 38 to 51 bushels per acre across all sites. No significant differences in soybean yields were detected in Michigan when soybeans were planted earlier (May 22) versus later (June 16), a possible strategy for ASR management. Another potential strategy, planting soybeans into a rolled cover crop, was evaluated for yield and disease effects in 2006 in Iowa, Pennsylvania and Michigan. Yields ranged from 22 to 38 bushels per acre in Michigan; up to 30 bushels per acre in Pennsylvania; but reduced in Iowa because of the drought.
Impacts
Impact: With the economic impact of ASR in organic systems ranging from $30 to $120 million in yield loss, this research has begun to identify potential strategies, such as copper-based fungicides and Bacillus pumilis for reducing loss in organic systems in the event of soybean rust. In areas where ASR has not yet arrived, methods of improving organic soybean systems, including reduced tillage and varietal selection for other soybean diseases can result in greater maintenance of soil quality and higher returns for farmers. Through the New Farm, New Ag Network, OrganicAgInfo and each institutions' organic websites, we have increased the knowledge base and skills of thousands of organic farmers across the U.S. in Asian soybean rust diagnostic and management tools.
Publications
- Delate, K. 2006. Soybean rust management for organic farmers. Iowa State University Organic Ag Website, Iowa State University, Ames, IA. Available at: http://extension.agron.iastate.edu/organicag/info/soybeanrustjune06.p df.
- Delate, K. 2005. Iowa State University studying soybean rust in organic production. The Organic Broadcaster 13(3):10.
- Delate, K. 2005. Researchers responding to discovery of soybean rust in the U.S. The Rodale Institute, Kutztown, PA. Available at: http://www.newfarm.org/columns/org_news/nov/rust.shtml.
- Hepperly, P. 2006. New hope for organic management of Asian rust in soybeans. The Rodale Institute, Kutztown, PA. Available at: http://www.newfarm.org/columns/research_paul/2006/0706/soybeanrust. shtml.
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