Anthracnose leaf blight in corn is caused by the fungal pathogen Colletotrichum graminicola.
The leaf blight phase of the disease typically shows up early in the season.
Anthracnose leaf blight does not generally have an impact on corn yield, as it usually only affects the lower leaves and corn quickly grows out of the disease.
Although they are caused by the same pathogen, the presence of anthracnose leaf blight has not been shown to correlate to anthracnose stalk rot later in the season.
Symptoms
Early symptoms appear on lower leaves prior to spreading up the plant.
Lesions are tannish brown with darker edges and generally spindly or oval-shaped.
On severely infected leaves, lesions may coalesce into large dead patches, causing the leaf to turn yellow and wither.
Necrotic tissues will have small spiky black fruiting bodies.
Life Cycle
The fungus overwinters as mycelium or sclerotia in corn residue.
Spores are spread primarily by splashing water during the spring.
Disease development is favored by wet weather during early crop growth with moderately warm temperatures.
Disease develops soon after planting and continues to develop until canopy closure.