Evaluation of the effect of different insecticides on the survival and capacity of Eretmocerus mundus Mercet to control Bemisia tabaci (Gennadius) populations

Abstract

Two different experiments were carried out to evaluate three insecticides. In the first one, the effect of two insecticides, methomyl and indoxacarb, on pupae and adults of the whitefly Bemisia tabaci (Gennadius) parasitoid Eretmocerus mundus Mercet was evaluated under laboratory and greenhouse conditions, using sweet pepper ( Capsicum annuum L.) plants. In the second experiment, oxamyl was tested to study its effect on the ability of E. mundus to parasitize and control B. tabaci in sweet pepper plants, using a greenhouse cage evaluation. Methomyl and indoxacarb caused low mortality of E. mundus pupae (17.6% and 7.8% respectively), although methomyl mortality was significantly higher. Methomyl produced 100% mortality on E. mundus adults with fresh and 24 h old residues on leaves, significantly higher than the mortality produced by indoxacarb (values ranged from 43.9% to 34.4%). The harmful effect of methomyl persisted for a long time (up to 60 days). The results of the experiment with oxamyl showed that E. mundus controlled whitefly population, without significant interaction between the presence of the parasitoid and insecticide on whitefly mortality. Whitefly mortality in the presence of the parasitoid was 87.8%, significantly higher than the mortality in the absence of E. mundus (59.3%). Oxamyl did not produce a significant effect on the emergence of E. mundus adults. Application of the products in IPM programs is discussed.