Soybean rust has been detected in three Southern Illinois counties: Massac, Pope and White. Samples from adjacent counties are being incubated for diagnosis. The finding of soybean rust was not unexpected, because Kentucky recently reported soybean rust in eight counties adjacent to Southern Illinois.
Since 1992, Dr. Suzanne Bissonnette has been an Integrated Pest Management Extension Educator with U. of I. Extension. Currently the Visiting Extension Education Soybean Rust Coordinator, she is co-director of the Extension Online Plant Diagnostic Clinic, editor of the Illinois Pest Management Handbook and Coordinator of the Champaign Extension Center.
How concerned is the agricultural community?
The finding of soybean rust in Illinois now will have no impact on the 2006 soybean crop, so immediate concern is nominal. Soybean harvest is well underway across the state, and areas of Illinois that have experienced a hard frost also will not be affected. However, there is significant concern about future growing seasons.
For 2 1/2 years an Illinois Soybean Rust Taskforce has been actively planning for the arrival of soybean rust. Participants include the Illinois Department of Agriculture, U. of I. researchers, U. of I. Extension, agrichemical companies, applicator makers, the Illinois Soybean Association, and the Illinois Farm Bureau. Each group in the taskforce has unique concerns in dealing with this disease. For instance, prior to soybean rust being detected in the U.S. there were virtually no fungicides labeled for use on soybeans. Today there are many product choices.
Additional concerns were raised about the supply of fungicides, should an epidemic break out in many states at once. Applicators had the concern that fungicide application in soybean was not something that our Illinois producers were familiar with since application methods differ greatly from herbicide application. Extension and the producer organizations needed to prepare educational programming and materials.
And then there was the question of sampling, scouting, and detection protocols. Because this pathogen was considered a significant threat to U.S. agriculture and a potential agent of bioterrorism, numerous federal agencies have been involved in the entire planning and discovery process. All in all, this represented a unique process for dealing with a new plant pathogen.
What does this mean for soybean farmers in Illinois for this year and next?
Producers can remain confident that our systematic approach for detection and monitoring soybean rust will be in place next year to alert them to the threat of soybean rust in their area. For the past two years we have had several methods in place for detection, the most extensive being our sentinel-plot system consisting of 40 field plots sampled and scouted through out the growing system. We have various methods of tracking spore movement, and we can do quick sample diagnosis and turnaround both through our U. of I. Plant Clinic and our online digital diagnostic service (available at every county Extension office).
The big concern for producers is whether soybean rust will show up during the critical reproductive growth stages next season. There is no way to know that for certain. Weather and over-wintering of the disease along the Gulf coast will be a significant factor. We just have to monitor that to stay ahead of the disease.
Is there a way to control soybean rust?
Here is the good news. We can effectively manage this disease with the proper and timely use of fungicides.
The bad news is that although soybean breeders are diligently working on detection and development of rust resistant soybean varieties, currently all of our commercial varieties are susceptible to the disease. Certainly this represents a very serious situation. Until resistance is available though producers we will need to manage the disease through fungicide application. Producers will need to plan for how to implement a fungicide program - first by determining if they will make the applications themselves or if they will hire a commercial ground or aerial applicator.
Timing is critical. If rust is imminent, applications need to be made prior to infection. Producers will also have to determine which type of fungicide they will apply. The choice changes if rust is already in the field. Also they will need to select which specific fungicide to apply, and then make a contingency plan if that product in unavailable. Scouting and staying current with the sentinel monitoring program will be critical.