Anthracnose leaf blight of corn caused by the fungus Colletotrichum graminicola is an economically important foliar disease of corn in New York State especially in no-till or reduced till fields.
The fungus overwinters on corn debris producing spores that infect the next year’s crop. Mild, wet conditions favor disease as spores are spread through rain splashing.
Anthracnose leaf blight occurs early in the growing season affecting lower leaves initially with late season disease progression affecting the upper leaves.
Use of resistant hybrids is the most effective control method available.
Since the fungus overwinters in crop residue, no-till or reduced-till practices can lead to an increase in disease when corn follows corn.
In cases where no-till or reduced-till practices are used, crop rotations for two to three years in conjunction with resistant hybrids would be an effective control strategy.
Early season symptoms appear as small, oval to elongate water soaked lesions on lower leaves. These semitransparent spots gradually enlarge to ¾ inch long and become tan at the center with red to reddish-brown or yellow-orange borders.
The entire leaf may become blighted as the lesions coalesce and severely blighted leaves will yellow and die.
During periods of wet weather, fungal fruiting bodies appearing as black specks may be found within the center of the lesions.
In late season, symptoms may appear on upper leaves.
- Anthracnose Leaf Blight Fact Sheet (PDF)