Association of N‐acetyl Loline and N‐formyl Loline with Epichloe typhina in Tall Fescue1

Abstract

The alkaloid fraction of tall rescue (Festuca arundinacea Schreb.) has been implicated in poor forage quality but the alkaloid content of tall rescue varies greatly amongrazing seasons, pastures, and individual plants. The objective of this research was to identify the association between the presence of E. typhina (Fr.) Tul. in the plant and the N‐formyl and N‐acetyl loline alkaloids. Plants were grown in benomyl‐treated soil in the greenhouse to control the fungus and treated plants and seed from treated plants were established in the field to provide seed and plant tissue for analysis. The fungus was eliminated or its development severely inhibited by growing tillers for 6 weeks in soil treated with benomyl.Accumulation of N‐acetyl loline and N‐formyl lollne in tall fescue was positively associated with the presence of the endophytic fungus, Epichloe typhina. Leaf tissue from treated plants contained very small amounts of N‐acetyl or N‐formyl loline. Plants from which E. typhina had been eliminated and that had been established in the field remained free of the fungus for at least 3 years.