Abstract
Evolution of resistance to the pyrethroid insecticide fenvalerate in the diamondback moth, Plutella xylostella (L.), was simulated by a computer model. Predictions from the model agree with data documenting development of diamondback moth resistance to fenvalerate in Ban-chau, Taiwan, in 75 of susceptible larvae to substantially delay resistance development. Adoption of alternative tactics for management of the diamondback moth is strongly urged.