Antibiotic and Deterrent Qualities of Endophyte-Infected Tall Fescue to Two Aphid Species (Homoptera: Aphididae)

Poor survival and reproduction of the aphid Rhopalosiphum padi (L.) was observed on tall fescue plants infected with the endophytic fungus Acremonium coenophialum Morgan-Jones & Gams. Reproduction was always much higher on uninfected plants, but on older infected plants, some R. padi survived long enough to molt and reproduce. In choice studies, R. padi and the greenbug, Schizaphis graminum (Rondani), preferred uninfected fescue plants. Greenbugs quickly destroyed their uninfected hosts and died. Those S. graminum that moved to infected plants also died. High numbers of R. padi on fescue plants could be a reliable indicator for the absence of endophyte-associated alkaloids that cause resistance to a number of other insect herbivores.