Soybean Rust Confirmed in Illinois

FOR IMMEDIATE RELEASE
October 8, 2009

Soybean rust (SBR) was reported and confirmed in several Southern Illinois counties on October 1^st, by Dr. Carl Bradley, State Extension Specialist for Soybean Pathology. The finding was reported on the Integrated Pest Management PIPE website, which is used to monitor movement of this pathogen within North America.

According to Bradley, although many double-crop fields in southern Illinois are still very green, all fields that he observed were past the point of soybean rust causing any yield loss. Soybean plants are most susceptible to rust from R1 thru the R5 growth stages, and all fields were at least at R5. Finding rust in Illinois is absolutely no surprise to Bradley, as rust has been observed recently in adjacent counties in Missouri and Kentucky.

This is the fourth year in a row that soybean rust has been found in Illinois; and there has been a concern this year that late planted beans might be more vulnerable if they were not past the R5 growth stage when the pathogen moved into our area. At this time however, fungicide treatments are not recommended in Illinois, because most soybeans are mature or at a point in their development and growth stage past the time where soybean rust can cause economic yield loss. Soybean plants at growth stages R1 to R5 are the only ones at risk of yield loss from SBR.
In Western Illinois, fields with double-crop beans or any late planted soybean fields where green leaves remain might be a good place to look for soybean rust. Dr. Loretta Ortiz-Ribbing, University of Illinois Extension Specialist in Macomb suggests to, "Look at the underside of the leaves in the lower canopy of soybean plants with green leaves and check to see if you observe any clusters of SBR pustules in small tan or red groupings. A 20X hand lens would be very helpful in this process."

"Even though soybean rust is not an economic problem right now, we would like to continue monitoring its spread, so we can confirm and verify models used to predict SBR spore movement." Please let Dr. Ortiz-Ribbing know if you think you may have found any suspect leaves.

The fungal organism that causes soybean rust does not survive the winter in Illinois. The spores of this pathogen have to move into the Midwest every season on air currents that move up from the Southern United States where the disease organism can survive the winter.

You can follow the movement of soybean rust and obtain more information by visiting the Pest Information Platform for Extension and Education (PIPE) website located at http://sbr.ipmpipe.org. Updated management guidelines are also available in the "management toolbox" located in the lower right-hand corner of the main page.

Source: Loretta Ortiz-Ribbing, Macomb Extension Center, (309)836-8366, ortizrib@illinois.edu