Southern Rust exploded across Southern Indiana in 2016 causing widespread yield loss. The disease has once again appeared in the state in 2017, but with much less severity. Brian Denning, agronomist with Stewart Seeds, told HAT that the cooler weather slowed the spread the past few days. “It tends to like the warm and humid weather, so these cooler temperatures is keeping the spread of the disease slow,” he said. Last week The statewide average temperature was 69.9 degrees, 3.1 degrees below normal. Statewide precipitation was 0.67 inches, below average by 0.24 inches.
Denning said he is assuming Southern Rust most likely exists in every county in SW Indiana, but warned growers not to confuse it with Common Rust, which does not have a yield impact, “An easy way to tell the difference is that Common Rust is darker in color and generally only on one side of the leaf.” He noted that later planted corn, mid-May or later, is the most susceptible to damage from Southern Rust.