The most common sign of ergot is the dark purple
to black sclerotia (ergot bodies) found replacing the
grain in the heads of cereals and grasses just prior to
harvest (Figure 1; a) rye field, b) wheat, c) various
grasses). The ergot bodies consist of a mass of vegetative
strands of the fungus. The interior of the sclerotia is
white or tannish-white. In some grains, ergot bodies are
larger than the normal grain kernels, while in other
grains, such as wheats, grain kernels and the ergot
bodies may be similar in size (Figure 2). A larger size
separation between the sclerotia and the grain kernel
simplifies the removal of ergot bodies during grain
cleaning.
Prior to development of the sclerotia bodies, the
fungus develops a stage in the open floret (flowering
head part) commonly called “honey dew.” The “honey
dew” consists of sticky, yellowish, sugary excretions of
the fungus which form droplets on the infected flower
parts.