Soybean Rust in Mexico: An Update

Craig Grau, Plant Pathology

Bryan Jensen, IPM Program

Thursday, April 27, 2006

A new development in soybean rust activity was recently report by Dr. Don Hershman, University of Kentucky, and Department of Plant Pathology.  His colleague from Mexico just reported 150 acres of soybean with an active soybean rust infestation.  This infestation is in the same area where soybean rust was previously found in a field harvested in early March.

 In the United States, soybean rust movement appears to be at a standstill, for now.  The kudzu patch near Dayton, TX which had rust last fall has grown extensively, but there are no symptoms of rust.  Furthermore, there are no reports of rust in Texas’s sentinel plots.  Louisiana is reporting a severe drought that is delaying planting of soybean sentinel plots as well as affecting growth in established sentinel plots.  Additionally, Kudzu is greening up through out the southern states and soybean have been reported to emerge as far north as central Illinois However, no new positive counties have been reported since March. 

Sources of soybean rust inoculum in Mexico and Texas are believed to pose a greater threat to the Midwest than soybean rust inoculum in Florida and other southeastern states.  For more information on soybean rust, and to track its development, please go to the USDA soybean rust website at http://www.usda.gov/soybeanrust/

Wind patterns that affect Wisconsin are more likely to flow through Mexico and Texas and provide a more direct, if not quicker, pathway to Wisconsin as compared to weather patterns from Florida, Georgia and Alabama.  Perhaps, soybean rust will follow the known pathway of other rust diseases.  The activity of soybean rust in Mexico, Texas and Louisiana will likely be of more importance to Wisconsin than its activity in Florida and other Southeastern states.

Thus, the situation on soybean rust in Mexico is very relevant to soybean growers in Wisconsin.