The entomopathagenic fungus Neozygrites fresenii (Nowakowski) Batko was the causal agent of epizootics in cotton aphid (Aphis gossypii Glover) on cotton in Arkansas during 1989, 1990, and 1991. Epizootics were widespread throughout the state, occurring in Drew, Desha, Lafayette, and Jefferson, Lafayette, Lee, Little River, Phillips, and Washington counties in 1990 and 1991 respectively. Fungal epizootics resulted in rapid declines of aphid populations in less than two weeks.