Alert: Toxic Ergot Prevalent in Brome Grass and Rye This Year

June 30, 2000
Ergot is very prevalent along unmowed fencerows and in pastures this year. I also ran into some ergot on rye in Mason County, as well. Matt Montgomery of the Sangamon/Menard Extension unit reports very evident ergot in that area, and I have had reports from the Effingham area, as well. It's been cool and wet, and that's what this disease likes best.

Ergot sclerotia on grass heads.

Ergot is a fungal disease of the seed head of about 200 wild and cultivated grasses and opened-pollinated small grains like rye. The fungus Claviceps purpurea is the most common cause of ergot. The fungus infects the seed head, and a prominent black sclerotium develops instead of a grain kernel. The sclerotia are larger than seed and a little curved. They are not hard to see.

Infested grain is a concern because the fungus produces very potent toxins that affect both humans and animals. Grain that exceeds market tolerance of ergot is discounted in value because it is a toxicity risk. Ergot poisoning primarily affect cattle that eat the ergoty grass heads or cleanings from contaminated grain. Toxins in ergot sclerotia contain a number of alkaloids, and one of the most common symptoms is constriction of blood vessels in the extremities. This results in lameness, hoof sloughing, and ear and tail tips falling off.

Grasses should be inspected for ergot before allowing grazing this year. You can control this disease very effectively in grasses just by mowing before seed is produced (not a solution for cultivated rye, though). Rye should be inspected and cleaned.--Suzanne Bissonnette

Author: Suzanne Bissonnette

The Pest Management and Crop Development Bulletin
Executive Editor: Kevin Steffey, Extension Entomologist

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