Survey of tall-fescue pasture: correlation of toxicity of Fusarium isolates to known toxins.

Several aspects of fescue foot in cattle suggest that this disease is caused by fungi growing on fescue grass. Certain fungi isolated from winter pasture yield toxins when grown on synthetic medium. Most of these toxin producers belong to the genus Fusarium. All but 1 of the 21 toxic and 7 questionably toxic Fusarium isolates produce either 4-acetamido-4-hydroxy-2-butenoic acid gamma-lactone, or 4beta, 15-diacetoxy-8alpha-(3-methylbutyryloxy)-12, 13-epoxytrichothec-9-en-3alpha-ol, or both.