Lesions resemble elongate rectangles on leaf surfaces.
Lesions have straight or parallel sides.
The disease can be found throughout the state at some level, but is most prevalent in east central, southern and western Ohio. Severe epidemics occur in continuous corn, reduced tillage fields in river bottoms or in locations with restricted air drainage. Lodging may result from excessive leaf blighting. Periods of drying between these periods also is important. Lesions generally first appear near tasseling and disease spread occurs until maturity.