Lesions may coalesce and blight entire leaves. Leaf blight may be followed by top kill and stalk rot. Leaf blight rarely causes large yield losses. Favored by cool to warm, wet, humid weather, continuous corn with reduced tillage. Cleanly plow under infected residue.
Initial symptoms are chlorotic flecks on leaf surfaces.
Flecks develop into oval to elongate reddish brown powdery pustules on upper and lower leaf surfaces. Reddish brown spores break through the leaf epidermis. Pustules become brownish-black as they mature. Usually not a serious disease in hybrids. Spores blown into the Midwest from the South.