Frogeye Leaf Spot of Soybean

Frogeye leaf spot, a fungal disease of soybean caused by Cercospora sojina, is becoming more common in Nebraska. In some years it may hasten soybean maturity by causing premature defoliation. Currently, only a few Nebraska fields have been affected severely enough to require treatment to protect soybean yields.

National yield loss estimates due to frogeye leaf spot have been reported to be as high as 30 percent when extensive leaf blighting occurs, but Nebraska estimated losses, even in highly susceptible varieties, are usually less than 20 percent. The disease is most severe when soybeans are grown continuously in the same field, particularly in reduced-tillage systems, since the pathogen is residue-borne.