Small, oval to elongated water-soaked lesions enlarge to become brown, spindle shaped spots with yellow to reddish brown borders. 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.
Stalk rot phase is most important.
Resistant hybrids, rotate corn with nongrass crops. Cleanly plow under infected residue. The resulting rhizomycelim occupies cells and is eventually converted to a sporangium containing sporangia on leaves and stalks. Stalk breakage may occur. First appear as small water-soaked lesions on the leaves then lesions enlarge and become chlorotic then necrotic with a tan center and dark brown or purple margin.