Herbivore Response to Naturalized Tall Fescue and Its Endophytic Fungus

Varieties of endophytic fungi have been known to increase its host grass’s resistance to drought, photosynthetic efficiency, and resistance to herbivores. However, it is common for these grasses to produce alkaloids that cause toxicosis in cattle and other organisms of higher trophic levels. We tested the performance and preference of Rhopalosiphum padi (cherry-oat aphid) after feeding on grasses of various levels of infection hailing from three locations as well as grasses with different endophyte hybrids. We found that the aphids built larger populations on naturally and mechanically uninfected grasses as well as on grass infected with sexual endophytes than on other hybrids or the infected fescue. There was also no preference between grasses of different collection sites. We conclude that R. padi is sensitive to the presence of endophytic fungi