Lethal and sublethal effects of Spinosad on some biological and biochemical parameters of Helicoverpa armigera (Lepidoptera: Noctuidae)

Cotton is one of the most widely used industrial products in various industries and is attacked every year by the cotton bollworms, Helicoverpa armigera H & uuml;bner (Lepidoptera: Noctuidae). In this study, we investigated the effect of the spinosad insecticide on some biological and biochemical parameters of the cotton bollworm . Bioassays were performed by using 3 rd instar larvae fed with artificial diets containing lethal (LC50) , and sublethal (LC15) concentrations of spinosad. Lethal and sublethal concentrations were estimated to be 0.90 and 0.35, mg a.i./kg, respectively. Compared to the control, lethal and sublethal concentrations of spinosad significantly increased larval and pupal development time, decreasing their weight. In addition, only LC50 of spinosad significantly reduced the fecundity and lifespan of adults as well as the hatching rate of the pest compared to LC 15 and control. Moreover, lethal and sublethal concentrations of spinosad reduced carbohydrate and glycogen content and did not change lipid content. A significant decrease in protein content was observed only after exposure to LC50 . At LC50 the activities of glutath ion e S-transferase (GSTs), alpha- and beta esterase were significantly reduced compared to LC 15 and control. The results of this study showed that LC50 and LC 15 of spinosad affect several biochemical and biological parameters of H. armigera . Therefore, spinosad at the lethal and sublethal concentrations can be included in integrated pest management (IPM) for this pest.