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Posted 10 November 2008. PMN Crop News.

Soybean Rust Confirmed in Illinois

University of Illinois at Urbana-Champaign.

Urbana-Champaign, Illinois (October 31, 2008)--Last year on October 22nd, soybean rust (SBR) was reported and confirmed in McDonough County. This year on October 22nd, the first SBR report was found in McLean County by Kevin Black with Growmark. Dr. Carl Bradley, State Extension Specialist for Soybean Pathology, confirmed the presence of soybean rust and reported it on the Integrated Pest Management PIPE website, which is used to monitor movement of this pathogen within North America.


The field with soybean rust was a late-planted double crop field, so the soybean plants still have green leaves. The incidence of soybean rust in the field was low, approximately 3 percent.

In Illinois, fungicide treatments are not recommended 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 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 Updated management guidelines are also available in the "management toolbox" located in the lower right-hand corner of the main page.

Loretta Ortiz-Ribbing
Macomb Extension Center