A mild summer spared most northeast Arkansas soybean fields from aerial blight, but University of Arkansas Division of Agriculture scientists would like to see relief for all growers, every year.

“Aerial blight is typically restricted to the northeast corner of the state,” said plant pathologist Dr. Cliff Coker. “Clay and Lawrence counties usually take the brunt of it. Early on, in 2004, we had some problems with it, but as the weather cooled off, we saw it fade away some.”

Growers sprayed fungicide for a range of diseases on about 600,000 acres in 2003. “We were bumping up against a million acres in 2004,” Coker said.

With that level of reliance, it’s important to use fungicides efficiently. Coker is working with Dr. John Rupe and other UA plant pathologists to determine the most effectual fungicide applications for aerial blight. They are also studying how variety selection might be used to help manage the disease.

“We want to know the best timing to apply fungicides and which cultivars are less susceptible to the disease,” Rupe said.

Because the fungus that causes aerial blight also causes sheath blight in rice, Rupe said they are conducting tests to see if controlling it in rice has a beneficial effect on soybeans planted in rotation in the same fields.

“If you control it in one crop, do you have to control it in the next crop in rotation?” he said.

Drs. Craig Rothrock and Rick Cartwright are also working on this research, funded in part by the Arkansas Soybean Promotion Board.

Coker said aerial blight knocks the pods off of soybean plants and causes them to delay maturity. “It’s real inconsistent,” he said. “You can look at a maturing field and see scattered green spots mixed in with the brown plants.

For now, he said, early planting Group IV soybeans can help avoid problems with aerial blight. Quadris, a broad-spectrum fungicide that also will help control other fungal diseases, is the application to use for aerial blight.