Ergot fungus infects wheat during flowering from spores released from sclerotia near the soil surface. Chance of infection is increased by cool, wet weather that prolongs flowering and by conditions (i.e. frost injury) that cause floret sterility. Infected florets initially exude a sticky honeydew containing spores that be spread to other florets by wind, rain and attracted insects. Infected florets eventually develop dark, hard horn-like structures called sclerotia instead of normal kernels. Barley, rye, triticale and numerous grass species are alternate hosts. Sclerotia returned to the soil with the straw and chaff or with contaminated seed stocks perpetuate the disease between cropping seasons. Ergot sclerotia also contain toxic alkaloids that reduce the value of wheat sold for food or feed.