Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
On August 24th, soybean rust was confirmed in a commercial field at the R8 growth stage in Willacy County, Texas in the far southern tip of the state. On August 22nd, soybean rust was detected on soybean leaves in a research plot in Decatur, Georgia. Tropical Storm Fay dropped a lot of rain in the Gulf Coast states but it will take some time to determine its effects on the spread of soybean rust. There were several new reports of soybean rust on kudzu in LA but none on soybean so far. The risk of rust is increasing in FL, LA, and southern GA, MS, and AL but there is very little infected kudzu or soybeans to produce spores in sufficient number to threaten the northern soybean production areas at this time – even if Gustav turns out to be a serious threat to the Gulf Coast. It looks as if soybean rust will not be an issue for DE growers again this year. Sentinel plots in all three counties are continuing to be monitored for soybean rust and other diseases. The only diseases that are being reported are low levels of Septoria brown spot and downy mildew. Neither disease should impact yields. Some late-planted double crop soybeans are beginning to die from drought.