Diplodia leaf streak of corn is a disease that has become more prevalent in Kentucky in recent years. It is commonly observed in fields in western Kentucky and is easily confused with other corn foliar diseases. Small, round, dark brown-to-tan lesions are first observed on leaves. Dark concentric rings may be observed in the center of early lesions at the infection site on the leaf. These lesions expand lengthwise in long streaks from the infection point and form elongated elliptical lesions. In severe cases, lesions can coalesce to blight large areas of affected leaves.