The presence of an endophytic fungus, Acremonium coenophialum , in tall fescue ( Festuca arundinacea ) deterred aphid feeding by Rhopalosiphum padi and Schizaphis graminum. Both species of aphid were unable to survive when confined to endophyte-infected tall fescue plants. Feeding deterrents and toxic factors to R. padi and Oncopeltus fasciatus , large milkweed bug, were primarily associated with a methanol extract obtained when endophyte-infected tall fescue seed was serially extracted with hexane, ethyl acetate, and methanol. The concentrations of pyrrolizidine alkaloids were determined to be 30 to 100 times greater in the methanol extract than in the hexane and ethyl acetate extracts.

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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.

Sixty-three male sprague Dawley rats were randomly assigned to dietary treatments containing 1) N-formylloline alkaloid (NFL), 2) N-acetylloline alkaloid (NAL), 3) NFL + NAL, 4) NFL + a mixture of ergot alkaloids, 5) NAL + a mixture of ergot alkaloids, 6) NFL + NAL + a mixture of ergot alkaloids, 7) a mixture of ergot alkaloids, 8) endophyte-free tall fescue seed (EFTF), and 9) endophyte-infected tall fescue (EITF) seed (negative control). All diets were prepared by mixing the prepared treatments and Laboratory Chow (1:1 ratio) and were fed at a maximum of 15 g per rat per day. All rats were killed at termination (d 18). Rats fed the EITF consumed less (P < .05) than those fed all other treatments. Feed intake for rats fed the NFL + ergot alkaloids was lower than for those fed NAL, NAL + ergot alkaloids, NFL + NAL + ergot alkaloids, ergot alkaloids, and EFTF treatments. Average daily weight gains (ADG) followed a trend similar to feed intake with some exceptions. Rats fed the NFL + NAL treatments had higher (P < .05) ADG than those fed all other treatments except the NFL + NAL + ergot alkaloid treatment. Rats fed the EITF had lower (P < .05) ADG than those fed all other treatments except those fed ergot alkaloids and NAL + ergot alkaloids. Epididymides, testes, hypothalamus, corpus striatum weights, prolactin and alkaline phosphatase content were not altered by dietary treatments. Results suggest that loline alkaloids may have a slight depressing effect on feed intake.

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