Southern corn rust on a corn leaf.
Southern corn rust on a corn leaf.

Southern corn rust was found June 1 in a Seminole County in Georgia. Only a small amount was found on corn at the R2/blister stage, which was older than most of the corn in Georgia at the time. Southern corn rust is considered the most important disease affecting corn in Georgia, according to Bob Kemerait, University of Georgia.

The disease can spread rapidly in storms and also with irrigation. Conditions had been favorable for development and spread. Kemerait recommended that growers hold off spraying until the researchers find rust.

"Now that we have found it, I have enough respect for the disease to say that growers in the southwestern part of the state whose corn has reached (or is about to reach) tassel growth stage an application of fungicide to protect the crop," Kemeraite said. "Growers in other areas removed from extreme SW Georgia should consider to monitor the spread of the disease. Some may want to make fungicide application either as 1) a safeguard or because 2) they are already making a trip across the field to spray something else."

Kemerait also explained that growers may have multiple fungicide options to control southern corn rust, including tebuconazole, as long as the field does not have northern corn leaf blight. If farmers have NCLB, growers are recommended to apply a strobilurin or fungicides that include a combination of strobilurins, triazoles and SDHI active ingredients.

In addition to southern corn rust and NCLB, Asian soybean rust has also been found in Georgia on kudzu in the counties: Miller, Baker and Grady.