Northern corn leaf blight (NCLB) symptoms usually appear first on the lower leaves.
“Spores are dispersed by wind and splashing water. Disease development is favored by extended periods (>6 hours) of leaf wetness (rain or dew) and moderate temperatures (64-81°F). ”
Caused by the fungus Setosphaeria turcica, leaf lesions start gray-green, turning pale gray or tan as the lesions age. Lesions range in length from 1 to 6 inches and are elliptical in shape. Spores are dark gray and occur under moist conditions. Typically on lower leaf surfaces.
Entire leaves can die if NCLB is severe enough. Although lesions can occur on outer husk of ears, kernals are not infected. Hybrids (monogenic or polygenic) resistant to NCLB exist but dependant on the type will either only be resistant to one type of the pathogen or to all but not absolute. Practicing crop rotation and residue reduction can decrease the chances of future NCLB presenting. In addition, several foliar fungicides labeled for NCLB exist.
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