TOXIC ENDOPHYTE-INFECTED TALL FESCUE AND RANGE GRASSES - HISTORIC PERSPECTIVES

A historic profile of endophyte-induced tall fescue toxicosis is prese nted. A chronology of events is presented, beginning with the importan ce of finding Balansia-infected grasses in a tall fescue pasture in no rth central Georgia. This initial finding was followed by the discover y that another related endophyte was present in tall fescue and other major forage grasses. This species of endophyte was identified as Acre monium coenophialum. After this report was the important discovery tha t cattle performance was poor on Acremonium-infected tall fescue. Thus , this endophyte and its presence in tall fescue was implicated as the cause of tall fescue toxicosis and fescue foot. It was later establis hed that this endophyte also produced ergot alkaloids. The related end ophyte of perennial ryegrass, A. lolii, was subsequently shown to be r esponsible for the ryegrass staggers syndrome. Several other species o f Acremonium have been associated with other important forage and turf grasses. Finally, important papers leading to the revelations that en dophytic fungi and their grass hosts are ecologically significant and that most should be considered mutualistic symbioses are reviewed. Sym biotic grasses have enhanced physiological and morphological character istics that offer biotechnological exploitations on one hand, but on t he other solutions to the toxicity of tall fescue are difficult becaus e grasses free of their fungal partner are generally ecological failur es.