Effect of Some Pesticides on the Predatory Mite Agistemus exsertus1

Abstract

The susceptibility of Agistemus exsertus Gonzalez to tetradifon, phosphamidon, trichlorfon, and carbaryl was determined using the Potter tower technique. The following concentrations of formulation were tested against the egg, protonymph, and adult stages; 0.06 g, 0.17 g, 0.5 g, 1.5 g, and 4.5 g of pesticide in 100 ml water. Phosphamidon, trichlorfon, and carbaryl had no toxic effect on the egg stage at any concentration. Tetradifon caused only 21.6% mortality when applied at the 4.5 grate. Protonymphs were more susceptible than eggs. All tested compounds were lethal to nymphs of A. exsertus but only at high doses which are not practical for use in the field. Tetradifon, carbaryl, and trichlorfon caused no mortality of adults at any concentration. Phosphamidon was relatively toxic to adults at higher doses between 1.0 and 4.5 g.