The fungal pathogen Colletotrichum graminicola is the
causal agent of anthracnose in corn. Anthracnose is common early in the season in
fields where debris from the previous year was left
on the soil. This early season disease phase is generally more severe in
fields where continuous no-till corn has been grown. It causes a leaf spot disease when corn is in the
seedling stage. The pathogen is disseminated by wind and rain
Plants become somewhat resistant to the leaf-spotting phase as the crop develops. If
weather conditions are favorable for continued development of the disease (high moisture and moderate temperatures), plants become susceptible to the "top-dieback"
and stalk rot disease phases later in the season.
anthracnose at the seedling stage should alert scouts to watch
for the disease later in the season. The fungus also affects a number
of grass species. The presence of infected grasses in or near corn fields could represent a continuing source of new infection.