Duration: 10/01/2006 to 09/30/2011

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Nature and Significance of Issue for Which Multistate Coordination is Proposed:

The need as indicated by stakeholders. The single largest factor facing soybean producers during 2005 is when to spray. It is very clear that protective/preventative and curative pplications, spraying shortly before spores arrive in a given field provides the best control. But spray applications too early may result in a wasted spray and resources and spraying too late will result in significant yield loss. Producers, representing both United Soybean Board and North Central Soybean Research Project eloquently stated (USDA-ARS Soybean Rust. Baltimore, December 2004) that there primary goal is to have the best information for fungicide timing and a more long term goal, identifying new sources of resistance.

The importance of the work, and what the consequences are if it is not done. Soybean rust remains the greatest potential threat to soybean production in the US. Its introduction and subsequent establishment will require major increase in the use of fungicides, greatly expanded efforts for identification and verification of sources of resistance to the rust fungus, and examining significant changes in soybean cultural management practices are now required. Without well planned studies, growers may abandon well developed management strategies and either spray too much or too little, losing valuable resources in the process.

The technical feasibility of the research. Fungicide trials, germplasm and cultivar evaluations, using established protocols will be conducted. These protocols will be adapted for studying soybean rust as needed. Results of these research efforts will be immediately adapted and communicated through national, regional and state Extension networks to our stakeholders.

The advantages for doing the work as a multistate effort. We will have differences across the regions for onset of disease, differences in pest/pathogen spectrum, cultivar responses, maturity groups, cropping practices, and environmental impacts. This multi-state effort will address these heterogeneous issues. The disease may also not occur in each region at the same level of severity each year. Sharing results across states will expedite the development of effective management strategies. The critical impact of these multi-state studies will be effective and economical management practices for soybean rust adapted to each of the US soybean production practices.

How the Proposed Activity Addresses Nation and/or Regional Priorities
NC504 has proven crucial to providing training for identification of soybean rust to Land Grant Pathologists. Training at Ft. Detrick during 2004, was critical for Dr. Ray Schneider, in being able to recognize Soybean Rust in field plots in Louisiana. In addition, this group received a grant from USDA-CSREES through Smith-Lever Special Needs Funds in which they developed a number of materials for producer education and training. These included preserved soybean leaves infected with soybean rust, soybean rust identification card as well as a fungicide manual. With an invading pest there is a tremendous need for information on the biology of the pest in its new environment, its distribution across the soybean production areas, etc. This project will focus on identifying information needs and coordinating research, education and extension across states and regions. Activities will involve scientists not only from states in the North Central Region but also from states in other regions which will probably incur soybean rust first. Coordination is critical, because there is a great pressure in each state for action as well as on USDA agencies.

Types of Activities:

Sentinel plot system: During 2005, sentinel plots were placed in all soybean producing states funded first through North Central Soybean Research Program and United Soybean Board, but USDA as well. These plots have been crucial in monitoring the development of disease and providing producers with an accurate risk assessment of soybean rust for each state. These types of diseases can easily impact a region, so multi-state coordination is crucial in following the course of disease development.

Development and evaluation of reliable spore traps: There was great confusion and unnecessary angst engendered by the observation of urediniospores in spore traps placed strategically along the southern tier of states. The reason for these reactions is that there was no way to confirm the identity of the spores that were trapped on the glass slides. In one case in Louisiana, three spores were observed on one slide that may have been the soybean rust pathogen. A press release had to be issued with the message that there was no need for alarm because the identity of the spores could not be ascertained. There is no need to deploy these traps in the future if we know that we will not be able to form sound conclusions based on microscopic observations of slides. However, if spore identities can be confirmed in a timely manner, spore traps, in combination with the predictive models that are currently under development, would be extremely valuable in formulating tactical and strategic control decisions. The technology to develop such reliable spore traps is available.

Identify sources of slow rusting resistance is a very high priority among soybean pathologists across the US. Evaluation of all of the US germplasm, under US production systems in the field, will be critical to identify these sources. Once sources are identified, then plant breeding and mapping these resistance loci will become a priority. Currently, many states have been incorporating more diverse backgrounds (China and South Korea) into elite breeding lines in an attempt to diversify the US soybean as well as exploit novel sources of resistance to many of the plant pathogens and pests that are limiting production (Phytophthora, Soybean cyst nematode, soybean aphid, soybean viruses, drought resistance). Identifying sources of resistance for soybean rust is a first priority but in the long-term, incorporating this into soybean cultivars that are adapted to each of the region and still have resistance to the local pathogens and pests will be important (ie: one location can not breed or develop germplasm for the myriad of soil types and regional differences that exist in soybean production in the US).

Evaluate commercial germplasm for yield stability in the presence of soybean rust. It is possible that some commercially available cultivars may already possess some slow-rusting characteristics for soybean rust.

Identify locations and mechanisms of overwintering in Southern US. The key to the development of epidemics each year will be the geographic location of survival of spores as well as the level of inoculum. Included here are assessments of volunteer soybeans throughout the winter in common rotation crops such as sugarcane and around equipment sheds and grain loading facilities at river ports. Establishing sentinel plots in cold frames and in greenhouses beginning in January of each year will provide valuable information regarding the presence of inoculum in the southern U.S. each year.

Evaluate cultural practices. Evaluation of cultural practices on the development of soybean rust- Row widths, plant population densities, impact on double crop, planting date by maturity groups on the development of soybean rust.

Identify and evaluate additional hosts as potential overwintering sources as well as their impact in contributing inoculum to soybeans. Additional hosts may serve as an early season inoculum source (additional hosts may not overwinter the pathogen, but if they are susceptible before the soybean crop, they may intercept inoculum early in the season that will spread to the soybean crop. This would be like overwintering if rust blows in early in the spring). In addition, what role these alternative hosts play as inoculum source also during the season needs to be determined. Determining the identity and role of additional hosts is critical to the development of reliable disease forecasting schemes.

Epidemiology/Prediction systems. Widely available, tested and validated prediction systems will be necessary to avoid unnecessary fungicide applications throughout the soybean belt to ensure the growers profitability. This system must be established in that it will be in place for many years to come. The occurrence and arrival of the soybean rust into each of the states will be dependent on the environmental conditions that occur each growing season as well as the amount of inoculum that overwinters each year. A full understanding of the epidemiology of this rust as it develops and spreads in the US will be critical to successful management in the future.
" Research is needed on better definition of temperature/leaf wetness/rainfall requirements for infection and the temperature requirements for latent period. This will help determine the environmental conduciveness for disease.
" Understand the aerobiology of soybean rust with emphasis on how the pathogen moves short, medium and long distances, how the level of disease in the field affects movement of the pathogen in the field and out of the field, and determine the conditions for spore survival in the air. As part of this, comparison of air sampling strategies for the most accurate means to sample soybean rust is required.
" Evaluation of spore trapping systems. Numerous technologies now exist and formats that monitor spore trapping and allergens. In addition, there are issues regarding the interpretation of these data, during 2005, soybean rust-like spores were found in traps in Louisiana, Tennessee and Kentucky; but conclusions regarding these findings consisted of caveats and disclaimers. What these findings indicate with regard to overall epidemic development will be critical to future predictions and management recommendations.
" To develop a model system to project mid-term disease outlook for industry (soybean producers and chemical companies) to make fungicide distribution decisions months before a growing season.

Develop coordinated survey and monitoring systems. An assessment of a sentinel plot system to monitor the spread and disease development of soybean rust through the US is required to determine if this can accurately assess the risk of soybean rust infection in a given region. Survey protocols for assessing the incidence, severity and damage of soybean rust in any given field are also needed. The detection and verification of soybean rust in each state is crucial to supplying the best disease management information by University Soybean Extension specialists to the US soybean producers.

In order to speed up information delivery to soybean producers, a coordinated web-based SBR reporting and forecasting system has been established (http://www.sbrusa.net/). The system has allowed NC504 members/Soybean Extension pathologists to enter in a restricted area of the website and feed new monitoring information to the system (http://aphis.zedxinc.com/login.html). Accordingly, new predictions on disease movement in soybean production region will be made. Risk information in the website will be presented in text and map format suitable for soybean producers. APHIS is coordinating this website to date, but these efforts will need to continue for the future. NC504 provides a framework for this to take place.

Fungicide Application Technology. Soybean canopies can be tall (5 or more) and thick, depending on the geographic location and environmental conditions. In order to maintain competitiveness with South America, soybean producers must maintain the high-yield, narrow row production systems which favor thick canopy development. Research is needed on new equipment systems where fungicide can penetrate the canopy without drift concerns. Air-assist type spray systems, newer types of nozzles will be needed. In addition, the effects of row spacing, plant populations and canopy architecture on fungicide application efficiency will also need to be determined.

Coordinated fungicide trials. There are currently 14 fungicides which have Section 3 Section 18 labels for management of soybean rust. There are at least more products which may also be added to this list or have Section 18 labels still pending. The cost of these materials per acre ranges from $7.00 to $35.00. Each product has its strengths and weaknesses. Unbiased trials will be necessary to look at timing on crops, economics, efficacy, length of residual, as well as combination with other pesticides to reduce application costs. In addition, yield losses associated with soybean rust at different growth stages is needed to develop economic thresholds. Fungicide companies do support, in each state, a limited number of treatments, but this type of testing will require more funding for more locations and many more treatment scenarios. In order to increase the probability of getting good disease development for these types of studies, it would be advisable to apply mist irrigation over the entire plot areas. These systems are costly and cannot be purchased on typical nonrestricted funds provided by chemical companies. As part of these coordinated fungicide trials  other important questions can be answered.

" Fungicide trials will also determine the efficacy of these newly labeled fungicides on other soybean foliar and seed diseases. This will be especially critical for southern states (ie: frog eye leaf spot and southern stem canker) but also northern states which have seen an increase in Phomopsis and Soybean stem canker and Sclerotinia white mold.
" Evaluation of soybean maturity and seed filling time. For some portions of the U.S. environmental conditions will not be conducive for disease development at all times during seed fill. The effects of planting date, variety maturity, and seed fill period within a maturity group on rust development need to be evaluated. These evaluations could result in an integrated management program for soybean rust and could result in less pesticide usage.
" Unified Rating System: A common rating system will be developed. This system will allow better comparisons of results from across the soybean region. The system should be based on percentages (ie. percent incidence, percent severity) to allow for appropriate statistical analysis. The usefulness of using remote sensing in quantifying rust severity will be determined both form aerial and hand-held platforms
" Yield loss relationships associated with defoliation. Much of this work was previously been completed with conventional varieties and not with the current Round-up Ready. In addition, this work was focused on the responses to insect damage, soybean rust may have additional factors that may or may not enhance yield loss. These two types of soybeans do have different growth habits, so much of this work needs to be repeated.

Communication and Education Needs. Transfer information and management guidelines about soybean rust to the research, extension, producer and agribusiness communities. The NC504 committee has already developed and distributed a soybean rust ID card, preserved soybean leaves with rust, and a 60 page Fungicide manual. These activities have also received assistance from USDA-CSREES, USDA-APHIS, and Soybean Check-off support.
" Updating and changing of fungicide guidelines for 2006 based on 2005 data
" Continued development of training materials for education efforts for soybean rust.
" Preserved leaves of all of the foliar soybean pathogens
" Development of 4-page color management guide that summarizes fungicide recommendations based on regions.
" Develop training materials focused on fungicide application techniques.
" Develop DVD  for soybean rust training for 2005/2006 on fungicide management
" Need to develop some very good, clear scouting protocols for producersexpanded scouting
" Coordinated extension programming through PMN site
" Coordinated extension education sessions for detections, identification and management of soybean rust.

Objectives

Procedures and Activities

NCDC-202 was involved in a number of Research and extension activities during 2005.

Extension_
1. Development and distribution of a soybean rust ID card. This was accomplished through the efforts of Loren Giesler, University of Nebraska and colleagues from several states. 750,000 cards were printed and distributed throughout the region.
2. A 60 page soybean rust fungicide manual focusing on the very basics of fungicide application was developed. As of November 2005, 135,000 manuals were distributed in x states.
3. 75,952 Extension-education presentations from December 2004 to March 2005 on soybean rust in 18 states (AL, AR, IA, IL, IN, KY, KS, LA, MN, MO, ND, NE, NY, OH, PA, SD, VA by 25 extension plant pathologists.
4. Produced xx number of preserved soybean leaves with killed soybean rust pustules. These were produced in South Africa and shipped to the US and delivered to each state.
5. Assisted with American Soybean Association website to provide state specialists comment concerning soybean rust.

Research
1. Sentinel plot system for the south east and north central states. Dr. X.B. Yang (Iowa State University) and Dr. Loren Giesler (University of Nebraska) were able to obtain funding from the North Central Soybean Research Program and United Soybean Board to fund sentinel plots in each state. This was met with additional funds from the USDA. Field plots were scouted on a weekly and in some cases more frequently by representatives (extension educators) in each state. Soybean samples and findings (+/-) were sent to University Diagnostic labs and the State soybean specialists. Information from these findings was then uploaded to the USDA website (www.sbrusa.com) where the movement of soybean rust could be monitored through the season. The data collected from these plots was then used to develop and evaluate epidemiological models for the short term.
2. Spore sampling  J. Rupe, R. Schneider and J. Kurle are collobarating with 2 research teams evaluating spore samplers, spore collectors and verification techniques.
3. Hand held diagnostic kits  A.Dorrance, R. Frederick and D. Luster with another US Lab are developing these kits as well as several private industries.
4. Fungicide efficacy and timing trials- Participants in each state evaluated soybean rust fungicides for their impact on soybean yields during 2005. Only, Florida, Georgia and Alabama were able to evaluate the effects on soybean rust.
5. Evaluation of fungicides combined with insecticides and herbicides- Many states evaluated the impact of these combinations on crops. This was especially apparent in the north central region where aphids were a problem in some fields during 2005.
6. Impact of soybean rust fungicides on other soybean pest/pathogen systems
7. Evaluation of germplasm, commercial cultivars and soybean plant introductions and development of soybean populations with putative resistance to soybean rust
8. Evaluation/monitoring of overwintering (alternative) hosts for soybean rust

Expected Outcomes and Impacts

Projected Participation

View Appendix E: Participation

Educational Plan

1. Translate soybean rust ID card to Spanish and print an additional 2,000 cards
2. Update soybean rust fungicide manual and begin work on additional chapters for the next version
3. Continue to provide the most current research-based information on soybean rust to producers through newsletters, telephone hotlines, fact sheets, and oral presentations
4. Continue to develop and maintain websites for producers
5. Continue to support the USDA website (http://www.sbrusa.net/) with state commentaries as well as data from sentinel systems.

Organization/Governance

The NCDC-202 committee has an elected chair and secretary-treasurer. The Secretary-Treasurer is elected at the end of a business meeting, serves as Secretary-Treasurer for the next annual meeting and becomes chair the following year.

Literature Cited

Bromfield, K.R. 1984. Soybean rust, Monograph (American Phytopathological Society), No. 11. St. Paul, MN.

Kuchler, F., Duffy, M., Shurm, R.D., and Dowler, W.M. 1984. Potential economic consequences of the entry of an exotic fungal pest: the case of soybean rust. Phytopathology 74: 916-920.

Madden, L.V., and Wheelis, M. A. 2003. The threat of plant pathogens as weapons against U.S. crops. Annual Review of Phytopathology 41: (in press).

Miles, M. R., Frederick, R. D. and Hartman, G. L. 2003. Soybean rust: is the U.S. soybean crop at risk? APSnet Feature, American Phytopathological Society. Available at: www.apsnet.org.

Yang, X. B., Tschanz, A. T., Dlowler, W. M. and Wang, T. C. 1991. Development of yield loss models in relation to reduction of components of soybean infected with Phakopsora pachyrhizi. Phytopathology 81:1420-1426.
Pivonia, S., Yang, X.B. and Pan, Z. 2004 (?). Assessment of the Epidemic Potential of Soybean Rust in the United States. Plant Dis. (in press).

Attachments

Land Grant Participating States/Institutions

AL, AR, CO, DE, FL, IA, KS, KY, LA, MI, MN, MO, MS, NC, ND, NE, NY, OH, SD, TN, TX, VA, WI

Non Land Grant Participating States/Institutions

ARS/USDA, 1400 Independence Ave, SW, Rm 3859, S Ag Bldg, Washington DC 20250, fax 202-720-3191, Iowa Soybean Association, Ontario - ON MInistry of Agriculture, Food and Rural Affairs, United Soybean Board, USDA-ARS-Urbana, West Virginia Dept. of Agriculture