The fact that Mississippi went red this fall has nothing to do with politics. One by one, the counties in this Southern state went positive for soybean rust throughout the months of September and October.
Mississippi State University plant pathologist Tom Allen says most soybean fields were out of danger by the time rust became an issue. "However, this is the first year that we have found soybean rust in the same kudzu patch two years in a row.
The other Southeastern states have what is generally considered a ‘historically' infected kudzu patch where they find rust in that location almost every year,” he reports.
Kudzu is considered the main overwintering host for soybean rust. Allen is finding that some kudzu patches are susceptible to soybean rust, while others are resistant to infection.
Wet conditions during the Midwest soybean growing season set the stage for soybean rust, but a late start in the South limited the amount of inoculum available to blow northward, explains University of Illinois plant pathologist Carl Bradley.
"Even though the last three years have been similar with rust showing up late in the Midwest, we are still in the early stages of an introduction of an exotic pest and will not really know how all this will play out until we've experienced it for several years,” Bradley says.
"Several factors have to align for us to see soybean rust early enough to cause a problem in the Midwest, but it could still happen,” he adds.
The first outbreak of rust this year in Illinois was in a late-planted double-crop field that was still green.
Since January of 2008, soybean rust has been reported in 15 states. This includes 52 counties in Alabama, 32 counties in Arkansas, 24 counties in Florida, 29 counties in Georgia, three counties in Illinois, three counties in Kentucky, 27 parishes in Louisiana, 78 counties in Mississippi, one county in Missouri, five counties in North Carolina, one county in Oklahoma, 16 counties in South Carolina, two counties in Tennessee, five counties in Texas and four counties in Virginia. Rust was also reported in 10 municipalities (counties) in Mexico. Soybean rust is expected to spread northward until frost.