Ergot

Ergot is a fungal plant disease caused by species within the Clavicipitales order, most notably Claviceps purpurea. This pathogen specifically targets the ovaries of grasses and cereal grains, replacing the healthy grain with a dark, hard fungal mass known as a sclerotium or "ergot body," which contains potent toxins.

The disease primarily affects rye, wheat, barley, and various forage grasses. Susceptibility is highest during the flowering stage when the floret is open and exposed to airborne fungal spores. Plants that flower over an extended period or those suffering from nutrient deficiencies are generally at a higher risk of infection.

Early symptoms include the production of "honeydew," a sticky, sugar-rich exudate that contains fungal conidia and attracts insects. As the crop matures, the infected florets develop visible, elongated, dark purple or black sclerotia that protrude from the glumes of the ear, easily distinguishable from healthy grains.

Environmental conditions play a critical role in the development of ergot. Cool and wet weather during the anthesis (flowering) phase is ideal for spore dispersal and germination. The sclerotia fall to the ground at harvest, overwintering in the soil, and produce fruiting bodies (stromata) in the spring that release wind-borne ascospores to infect new crops.

The economic impact of ergot is significant due to the contamination of harvested grain with toxic alkaloids, which pose serious health risks to humans and livestock (ergotism). Management strategies include the use of clean, certified seed, deep plowing to bury sclerotia, rotating crops with non-susceptible species, and managing wild grass populations surrounding the field to minimize the inoculum source.