The insect growth regulator, Fenoxycarb, induced various morphogenetic aberrations in Notonecta unifasciata, Anax junius and Pantala hymenaea after treatment of late nymphal stages. Most affected nymphs died while molting from nymphs to adults. Fenoxycarb is also ovicidal to young eggs of N. unifasciata. The treatment rate of 0.034 kg AI/ha fenoxycarb induced some reduction in N. unifasciata population densities and produced a few morphogenetic abnormalities in some Odonata. However, planktonic organisms and aquatic beetles regularly found in the mosquito breeding habitats showed no deleterious effect.