Impact of organophosphorus insecticide, malathion on the progeny sex ratio of Pimpla turionellae L.

The effects of 0.001, 0.01, 0.1 and 0.5 ppm concentrations of malathion, an organophosphorus insecticide, viewed over the course of the experiment, on adult emergence and sex ratios of emerging adults of the parasitic wasp, Pimpla turionellae L. (Hymenoptera: Ichneumonidae) were investigated. Diets which contain 0.001 and 0.01 ppm malathion significantly increased the total adult emergence on day 13, 28 and 31 when compared to control diet. Although 0.01 and 0.1 ppm malathion increased the female emergence, higher concentration of malathion (0.5 ppm) significantly decreased the female emergence. Adult female emergence significantly decreased on day 10, 16 and 25 in the group which was fed with the meridic diet containing 0.5 ppm malathion. This study indicated that orally administrated high concentration of malathion (0.5 ppm) significantly decreased female emergence of P. turionellae.