NCERA212: Soybean Diseases
Statement of Issues and Justification
Mission The mission of the NCERA-137 Soybean Disease Committee is to provide researchers (university and federal), producers, soybean commodity groups, consultants, breeders and other soybean industry members with research accomplishments, educational information and management tools that will contribute to a better understanding of soybean diseases and their management options in the north central region. This coordinated, multistate research will assist soybean breeders, seed companies and fungicide manufacturers in developing improved germplasm lines, varieties and integrated pest management programs that will ultimately enhance the profitability of soybean production while protecting the environment and sustainability of soybean production in the north central region. .Statement of Issues and Justification General Background Information Processed soybeans are the largest source of protein feed and the second largest source of vegetable oil in the world and the U.S. is the world's leading soybean producer and exporter. In 2008, U.S. soybeans were planted on a total of 75.7 million acres with a total yield of nearly 3 billion bushels. The average price paid to farmers was $9.25 per bushel, giving the 2008 crop a value exceeding $27.3 billion. The north central region produces 80% of the soybeans grown in the U.S on approximately 60.7 million acres. Nature and Significance of Issue for Which Multistate Coordination is Proposed
Soybean production in the north central region has increased due to changes in management systems, improved genetics, and expanded soybean acreage. From 1996 through 2007, yield losses to soybean diseases were estimated at 13.5% (23). There are numerous opportunities for plant pathologists to work together to reduce yield losses caused by diseases through both improved cultivar resistance and best management practices. Best management practices include the reemphasis of integrated pest management principles whereby fungicide applications are made only when economic thresholds are reached.
One of the major strengths of NCERA-137 is the ability for its members to discuss and respond to new and reemerging diseases in the north central region. For example, soybean rust was discovered for the first time in the fall of 2004 near Baton Rouge, Louisiana (22). Numerous members of this committee were at the forefront of the national response prior to the creation of the NCERA-208 Soybean Rust Committee. While over the past four growing seasons, soybean rust has not caused the feared catastrophic losses predicted by some, the disease has spread in a decidedly different pattern each year, leaving pathologists unable to predict what the long term impact of the disease may be. As a result, its introduction has resulted in major increases in the use of fungicides, even in areas where rust does not occur. For example, according to data from the National Agriculture Statistics Service (NASS), very little fungicide usage occurred on soybeans prior to 2006. In 2006, over 362,000 pounds of fungicides were applied to soybeans, with that number continuing to increase in 2007 and 2008 (http://www.nass.usda.gov/Publications/Ag_Statistics/2008/2008.pdf). There are numerous questions regarding the efficacious use of foliar fungicides that still need to be addressed. Additionally, breeders continue to expend a large amount of their time in efforts at finding sources of resistance to the rust fungus.
In addition, the soilborne disease Phytophthora root and stem rot, has remained an important limitation on soybean yields and the importance of Sclerotinia stem rot and sudden death syndrome have increased due to climatic trends (warmer and wetter) and altered management practices (no-till and reduced till). NCERA 137 collectively serves as a forum to address these concerns, and plan research.
In spite of the fact that a great deal of emphasis has been put forth both in research and Extension efforts to manage soybean cyst nematode, there is increasing evidence that some populations of the nematode are now able to overcome the major source of resistance to the disease. This poses many questions on long term management of SCN, as well as the continued need for extension and outreach efforts to better educate stakeholders on the importance of SCN resistance and field sampling.
Research continues to be needed on the development of molecular techniques to diagnose pathogens that have spread from south to north. For example, the successful development of PCR techniques to confirm the existence of symptomatic and asymptomatic forms of the brown stem rot pathogen, Phialophora gregata, has provided new evidence that this pathogen is much more widespread than previously thought (14).
Charcoal rot, frogeye leaf spot, and bean pod mottle virus, diseases that were historically southern problems have continued to spread and have had negative production impacts in the north central region. Additionally, over the past several years, there are many new researchers and Extension specialists who have joined the ranks of the soybean disease research community. NCERA-137 has had a 25-year history of success and the benefits of new faculty participating in NCERA-137 are critical for effectively fostering new collaborations and communication of results for these new researchers.
How the Proposed Activity Addresses National and/or Regional Priorities
Meetings. Since its inception in 1984, the annual meetings of NCERA-137 have had near perfect attendance from member states plus Ontario, Canada and commodity groups. Participants place a high value on the interpersonal exchanges and it shows in the attendance rate and lively discussions. The annual meeting is routinely aligned with meetings of other groups interested in the health and productivity of soybean. For example, it is held every third year in conjunction with the Soybean Breeders Workshop and occasionally with the Southern Soybean Disease Workers Meeting.
Collaborations. Collaborations within NCERA-137 are the basis for numerous regional research projects and multistate grant proposals funded by groups such as the North Central IPM Center and the North Central Soybean Research Program (NCSRP) (see Collaborative Grant Proposals, below). In recent years, these coordinated regional projects have included regional research on Sclerotinia stem rot, Phytophthora root rot, brown stem rot, and sudden death syndrome and most recently a new soybean cyst nematode project.
Surveys. A regional disease loss survey of NCERA-137 researchers and Extension specialists provides annual yield loss estimates for the North central region (23). A joint effort of the United Soybean Board and NCERA-137 membership, this survey is a comprehensive assessment of soybean yield losses to plant diseases. Information from this survey is used to determine the relative importance of soybean diseases in order to prioritize research and guide breeding efforts.
Associations with other groups. NCERA-137 members maintain a close association with the NCERA-208 Soybean Rust and the NCERA-200 Soybean Viruses Committees in order to coordinate research on soybean rust and soybean viruses, emerging pathogens that are at the forefront of NCERA-137 members research and extension programs. NCERA-137 members also work closely with state and regional soybean commodity organizations.
Technology transfer and training. NCERA-137 members are extensively involved in technology transfer via traditional and electronic media. In addition to traditional state Extension publications, multi-state regional efforts are also ongoing. The Soybean Plant Health Initiative (PHI) (http://planthealth.info/index.htm) is a collaborative effort between the NCSRP and north central region soybean researchers and is accessible to producers, consultants, and researchers. Its website is a centralized source of soybean disease research and disease management information. Links to similar systems in each state extend the reach and content of the PHI.
NCERA-137 members, working collaboratively with the NCERA-208 Soybean Rust Committee, have played an important role in the development of the IpmPIPE (Integrated Pest Management Pest Information Platform for Extension and Education) that allows soybean producers, Extension educators and soybean industry personnel to follow the spread of soybean rust on a real-time basis.
NCERA-137 membership, as stakeholders in the activity of the committee, has influenced research directions on soybean diseases important in the north central region to the benefit of soybean producers, the ultimate customer for their efforts.
The continued success of NCERA-137 is contingent on our ability to actively train the next generation of researchers, teachers and Extension workers. Even though funding for graduate students and postdoctoral associates has become more difficult to obtain, we need to continue to seek new opportunities for graduate students and postdoctoral associates to study soybean diseases and to actively participate in activities associated with NCERA-137.
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