Gray Leaf Spot of Corn
Gray leaf spot (GLS)  caused by Cercospora zeae-maydis is considered the world’s most yield-limiting disease on corn. All corn hybrids, regardless of type, have some susceptibility to this disease.
Disease Symptoms
Early GLS symptoms include brown or tan spots 0.2 inches wide by 0.4-0.8 inches long, which span the region between the leaf veins. These lesions become irregularly-shaped to rectangular-shaped with yellow margins (more visible upon backlighting).
Early gray leaf spot lesions ,can be confused with other fungal diseases of corn such as anthracnose caused by Colletotrichum graminicola, eyespot caused by Kabatiella zeae, and early common rust pustules caused by Puccinia sorghi
Management
Implementing several strategies will help producers mitigate disease effects, although some strategies, while beneficial, may not fit into a producer’s cropping system. The best management strategy for gray leaf spot either delays the epidemic’s onset and/or slows the rate of disease development.
Fungicide management
Contact (Preventive) Products Containing Mancozeb
Dithaneâ„¢ , Dithaneâ„¢ M45 (Dow AgroSciences)
