Gray leaf spot, caused by the fungus Cercospora zeae-maydis, has developed since 1982 into one of the most important corn leaf diseases in Iowa. It is most common and severe in the southern half of the state. The pathogen survives well in corn residue on the soil surface. Because of the continuing and justifiable popularity of conservation tillage, it seems likely that this disease will be a chronic problem, and fungicides may be needed for its control. In 2000, we conducted a trial at the Southeast Research Farm (SERF) to evaluate fungicidal control of gray leaf spot on high-oil hybrids, which are more likely than standard hybrids to demonstrate an economical return from a fungicide application due to the higher value of the crop.