EFFECTS OF CHEMICAL ACARICIDES ON THE MORTALITY OF THE TWO SPOTTED SPIDER MITE Tetranychus urticae KOCH (Acari: Tetranychidae)

Abstract

Background. Chemical acaricides with different modes of action are an effective alternative for the management of T. urticae and to prevent the selection of resistant population. Objective. To evaluate the effect of chemical acaricides of different toxicological groups on the mortality of T. urticae. Methodology. To evaluate the acute toxicity, mites were exposed to leaf discs of eggplants that had been immersed in the acaricides. The mortality was recorded at 4 h period for a total of 48 h. To evaluate the residual effect, the acaricides were applied to eggplant plants, leaf discs were obtained at different periods (1 - 32 days after acaricide application) and T. urticae adults and nymphs were exposed to the leaf discs. Results. Abamectin, spirodiclofen and fenpyroximate had the fastest effects in adults and nymphs (4 h after application). Abamectin, spirodiclofen and fenpyroximate had long-term effects, for up to two weeks. Spirodiclofen, fenpyroximate and acequinocyl had also ovicidal effect. Implication. Chemical acaricides with different mode of action represent a viable option for the management of T. urticae and the prevention of the selection of resistant populations. Conclusión. Abamectin, spirodiclofen, and fenpyroximate are highly toxic against adults and immature T. urticae.