Northern Corn Leaf Blight

Exserohilum turcicum

Northern corn leaf blight lesion
Northern corn leaf blight lesion. Photo courtesy of University of Georgia Plant Pathology. Licensed under CC BY 3.0.
Northern corn leaf blight is a significant corn disease. As a fungal disease, it is most serious when there are prolonged wet, humid conditions.
Northern corn leaf blight lesions have a long rectangular "cigar" shape. Resistant hybrids have smaller lessions. Lesions are gray or tan in color and 1 to 7 inches long. Besides leaves, stalks and husks may also be infested.
Leaf with multiple northern corn leaf blight lesions
Leaf with multiple northern corn leaf blight lesions. Photo courtesy of University of Georgia Plant Pathology. Licensed under CC BY 3.0.
Northern corn leaf blight attacks the leaf tissues, reducing leaf area and hence yield. Damage typically begins in the lower leaves and moves up the plant, with the most severe damage occurring when the disease is at or above the ear leaf. The extent of lesion growth and hence damage is influenced by the resistance of the host plant.
Fungicides applied at VT-R1 provide some level of control of northern corn leaf blight. Treatment is most likely to be cost effective if the disease is at or above the ear leaf. Always read and follow all label instructions.
Crop rotation and tillage can help to reduce the level of disease in a field since the disease overwinters in crop residue.