ergot, fungal disease of cereal grasses, especially rye, caused by species of the ascomycete fungus Claviceps. The disease decreases the production of viable grains by infected plants and can contaminate harvests.

What causes ergot to grow?

An ergot kernel, called a sclerotium, develops when a spore of fungal species of the genus Claviceps infects a floret of flowering grass or cereal. The infection process mimics a pollen grain growing into an ovary during fertilization.

How do I get an ergot?

Early ergot fungus symptoms in grains and grasses are very hard to detect, but if you look at their flowering heads closely, you may notice an unusual shimmering or sheen caused by a sticky substance coming from infected flowers. This honeydew contains a huge number of spores ready to spread.