Head smut is a systemic disease of corn that
starts at seedling stage, and remains
asymptomatic until the plant reaches its
reproductive stage. Symptoms consist of
conspicuous galls that replace ears or tassels.
The galls are covered by a very fragile
membrane that breaks early and easily,
exposing masses of dark brown spores,
teliospores, and vascular bundles (Fig. 1). The
consistency of the membrane and the presence
of vascular bundles are what differentiate head
smut from common smut. Once the membrane
is broken, wind and rain spread the teliospores
into neighboring soil where they stay viable
for several years.