The best method of reducing gray leaf spot is rotation. The organism is specific to corn, so any other crop can be used. If rotation is not feasible, incorporation of debris into the soil, particularly following harvest, would help reduce the inoculum potential for the following year. Consider planting a fall cover crop where erosion is a concern. To date, the hybrids grown in Kansas have a range of resistance to the disease.
Some hybrids are extremely susceptible, while others appear to have a reasonable level of tolerance.
Only a few seed companies provide resistance information in their catalogs, and uniform field ratings are unavailable. A single fungicide spray has proven economical when infection begins early in the season. Fungicides cannot be applied after 50 percent of the plants in a field are showing silk. Therefore, adequate scouting must occur before silking. Usually, if lesions can be found on the leaf immediately below the ear leaf before the initiation of silking, a fungicide application should be made.