Alleviating Tall Fescue Toxicosis Problems with Nontoxic Endophytes

In 1943, a cultivar of tall fescue (Festuca arundinacea) later known as Kentucky 312 was released for sale. This cool season grass became widely distributed in the southeastern United States because it was persistent in the face of drought, grew on poor soils and provided good erosion control, as well as large amounts of forage for hay or grazing.2 By 1950, it was recognized that animals grazing tall fescue did not perform as well as forage analysis would predict.2 In 1977, research (Bacon) revealed the presence of an endophyte, Neotyphodium coenophialum, in the intercellular spaces of the leaf sheath. Later research connected this endophyte with what is now recognized as fescue toxicosis.4,5 With the discovery of the endophyte in tall fescue, the solution to the toxicity problem became obvious: remove the endophyte.1 With endophyte-free fescue, animal performance improved but the plants were not as hardy, and stand loss in endophyte-free fescue became a problem.3