By Kiersten Wise, Purdue University

As Indiana soybean producers well know, the risk of soybean rust to Indiana soybean production from year-to-year is hard to predict, and depends primarily on weather patterns and the level of disease that develops throughout the year in the southern U.S. Because of this, a sentinel plot system has been implemented in Indiana, and other soybean producing states, to monitor the seasonal, northward spread of soybean rust from the southern U.S.

Indiana has participated in the national effort to monitor the soybean crop for soybean rust using the sentinel plot system since 2005, and through this program, we have been able to detect soybean rust infections at very low levels in Indiana in 2006, 2007, and 2009. This monitoring system greatly improves our ability to detect soybean rust early enough to issue fungicide spray advisories, if needed.

What Indiana soybean producers may not know is that the sentinel plot system in Indiana also provides observations on many other diseases within the state. Soybean sentinel plots are monitored for potential disease threats to the soybean crop, and used to help determine distribution and severity of foliar diseases such as frogeye leaf spot, brown spot, downy mildew, and Cercospora leaf blight, to name a few. The tools we use to provide updates on soybean rust, such as the email list serve, the toll-free hotline, and the ipmPIPE Web site, also serve to distribute updates on foliar diseases as well as damaging diseases like SDS, white mold, and charcoal rot.

Indiana will once again participate in the national sentinel plot system, and will monitor 11 fields on a weekly basis for soybean diseases, including rust, beginning in June. Support for the monitoring program is provided by the Indiana Soybean Alliance. Weekly updates on soybean growth stages, crop condition, and disease observations will be posted online at the ipmPIPE web site ( by clicking on the state of Indiana on the national map. Producers are also able to track the movement of soybean rust at this Web site.

Indiana soybean producers can also subscribe to the Indiana soybean disease update list serve, at This email alert service will provide convenient and timely updates on soybean disease monitoring in Indiana, and also provide information on fungicide spray applications if soybean rust reaches Indiana at a critical time during the growing season. Purdue University will continue to maintain a toll-free soybean disease hotline, which is updated weekly beginning in late June. The phone number is 866-458-RUST (7878). We will also provide updated commentary in the Pest&Crop newsletter as the season develops.

SOURCE: Purdue University.