Toxicity of insecticides used in melon crop to Opius scabriventris, a natural parasitoid of Liriomyza sativae

Abstract

Opius scabriventris Nixon is an important parasitoid of the leafminer Liriomyza sativae Blanchard in the melon crop (Cucumis melo L.). Knowing the impact of insecticides on this parasitoid may help the integrated pest management, thus allowing recommending insecticides with a lower impact. Therefore, this study evaluated lethal and sublethal toxicities of select insecticides used in the melon crop for controlling leafminers on the O. scabriventris parasitoid. The toxicity of the insecticides was assessed by confining adults of the parasitoid on freshly sprayed plastic containers, under laboratory conditions. The evaluated insecticides were abamectin, chlorantraniliprole, cyromazine, spinetoram, spinosad, in addition to the negative control treatment (distilled water). The sublethal effect of the insecticides was studied through the parasitism of leafminer larvae by surviving parasitoids. Among the evaluated insecticides, abamectin, spinetoram and spinosad were the most toxic to O. scabriventris; while chlorantraniliprole and cyromazine demonstrated low toxicity to the parasitoid, albeit causing reduction in its parasitism capacity.