Ergot

Infected florets first exude a sticky, sweet-smelling fluid known as honeydew, which contains fungal spores and can attract insects. This stage is followed by the development of a hard, dark purplish-black sclerotium in place of the normal kernel, often protruding noticeably beyond the surrounding grain.

Sclerotia that fall to the soil, or that are returned with contaminated seed, can survive and germinate the following season to produce small, mushroom-like structures that release airborne ascospores. These spores infect open florets during flowering, and secondary spread can occur through insects and rain splash carrying the honeydew stage between florets.

• Sclerotia can persist in soil or as a grain contaminant between seasons
• Infection requires open flowers, so crops and grasses with an extended flowering period are more exposed
• Nearby infected grasses can serve as an additional source of spores

Rye is the most susceptible major cereal because of its extended open-flowering and cross-pollinating habit. Wheat and triticale can also be affected, with triticale generally more exposed than wheat because it shares some of rye's flowering characteristics. Many wild and forage grasses can also host the fungus.

• Cool, wet weather during the flowering period
• An extended or uneven flowering period, including in some hybrid seed production systems
• Nearby infected grasses or previous ergot-contaminated seed
• Reduced or delayed pollination that leaves florets open longer

Because ergot spreads through open flowers and persists as sclerotia, prevention combines clean planting material, field sanitation, and post-harvest grain cleaning.

• Use certified, ergot-free seed
• Rotate away from highly susceptible cereals and control grassy weeds and volunteer plants that can host the fungus
• Bury sclerotia through tillage where consistent with the local cropping system
• Clean harvested grain to remove sclerotia before use as food or feed