Lethal effects of hexaflumuron, spinosad, abamectin and indoxacarb on egg and third instar larvae of Cabbage white (Pieris brassicae L.) and its parasitoid (Cotesia=Apanteles glomeratus L.)

Cabbage white, Pieris brassicae (L.) (Lepidoptera: Pieridae) is an important pest of cruciferous in Iran and the world. In this study, the effect of four insecticides; hexaflumuron, spinosad, abamectin and indoxacarb on cabbage white and its parasitoid Cotesia glomerata L. was investigated The LC50 values obtained from the analysis of probit as a result of the effect of different concentrations of hexaflumuron, spinosad, abamectin and indoxacarb on the 3rd instar larvae of P. brassicae after 72 hours were (0.213, 0.298, 0.30 and 0.434) ml/L, respectively. The LC50 values obtained from the same insecticides on eggs of P. brassicae after 7 days were (0.831, 0.440, 0.267 and 0.489) ml/l, respectively. The results of the same compounds effects on parasitoid after 7 days showed that hexaflumuron and indoxacarb are the most harmful and abamectin is the least harmful for this natural enemy. The results showed that the most effective insecticides on 3rd instar larvae of P. brassicae during 72 hours was hexaflumuron. In the study of parasitization of third instar larvae of cabbage white under the influence of different concentrations of hexaflumuron, spinosad, abamectin and indoxacarb in compared with control, results showed at low concentrations of all four insecticides, there is no significant difference between control and insecticides, but there was a significant difference in higher concentrations and the mean number of third instar larvae in the control treatment increased. According to the results of this study, hexaflumuron can be suggested as a low-risk compound for parasitoid and effective against this pest.