Southern rust has been confirmed in four Jefferson County cornfields and University of Arkansas System Division of Agriculture experts are advising corn growers to scout for signs of the fungus in their fields.

Travis Faske, Extension plant pathologist, said Wednesday (June 20) that the disease appeared in Arkansas about a month after being spotted in Louisiana. Conditions that favor disease consist of high temperatures -- 80 to 90 degrees, high relative humidity, and frequent rainfall.

The fungus that causes southern rust, Puccinia polysora, creates round or oval pustules that are orange or light cinnamon-colored. In Jefferson County, symptoms appeared in “one of every 20 plants in the fields,” Faske said.

Jason Kelley, Extension agronomist, said southern rust shows up every year. “Right now, the concern is whether or not the corn is far enough along not to be damaged by southern rust. Producers should be scouting to see if any southern rust is present before deciding whether to spray a fungicide or not.”

Because southern rust can be confused with other diseases, growers unsure of the symptoms should bring samples to their county Extension office for testing.

Read more of Faske’s article about southern rust at Arkansascrops.com or contact your county Extension office.