In Vitro Growth of Acremonium coenophialum, an Endophyte of Toxic Tall Fescue Grass.

Acremonium coenophialum, an endophytic fungus present in toxic tall fescue grass and seed, grew very slowly or not at all with conventional media and cultural practices. However, a considerable increase in growth was achieved in a relatively dilute medium consisting solely of glucose and yeast extract. The optimal levels of glucose and yeast extract were 3 to 6% and 0.35% (wt/vol), respectively. The addition of salts which lowered the pH suppressed growth. Even when the pH was controlled, the addition of KH(2)PO(4) at a level of 3.2% or more greatly inhibited growth. A. coenophialum grew better in shake culture than in stationary culture. The optimal temperature was 23 degrees C, and the optimal pH was 6.5.