Northern Corn Leaf Blight
(Exserohilum turcicum)
Symptoms: Lesions initially develop as pale gray-green, cigar-shaped less than 1 cm long but expand 3 to 15 cm. As the lesions mature they become tan with distinct, dark zones of sporulation. While it can be commonly observed in Tennessee, it does not usually affect yield. Can also cause kernels to not be attached.
Risk Factors: Most damaging if there are prolonged periods of dew and moderate temperatures (64-80 °F) and if the infection occurs before sinking.
Management: Use of resistant hybrids. When practical, fungicides may be applied to leaves when lesions are first found (fungicide efficacy table).