Susceptibility of the 3 major mite species on cotton is a factor affecting efficacy of Comite^®, with Tetranychus turkestani being most susceptible, T. urticae intermediate and T. pacificus least susceptible. Laboratory studies on T. urticae showed that temperature, light, humidity, pH and mite density had little effect on the contact and residual activity of Comite^®. Fumigant activity was observed which increased with higher temperatures. Ovicidal activity was observed at high concentrations. Treated adult female mites oviposited some eggs before they died, however, larvae which hatched from these eggs were killed by residual activity of Comite^®. While some feeding damage was observed on Comite^® treated cotton plants, it was much less than on untreated plants. No translaminar activity was observed.