Lethal and sub-lethal effects of insecticides chromafenozide, pyridalyl and thiodicarb on parasitoid wasp, Habrobracon hebetor

Habrobracon hebetor Say, is one of the most important larval parasitoids of many lepidopteran pests, particularly the family Noctuidae. In this study, the lethal and sub-lethal effects of chromafenozide, pyridalyl and thiodicarb, as insecticides, were investigated on this parasitoid under laboratory conditions. Bioassay tests on adults were conducted based on contact method and sub-lethal effects were done based on demographic toxicology. According to bioassay tests, estimated LC30 values for chromafenozide and thiodicarb were 126.43 and 54.24 mg a.i./L, respectively. Since even with the application of three times more than that of the field concentration of pyridalyl (2250 mg a.i./L), maximum mortality percentage of insects was 19%; LC30 value was not estimated for this insecticide. In order to assess sub-lethal effects of insecticides, female wasps were exposed LC30 values of chromafenozide and thiodicard and the field concentration of pyridalyl (750 mg a.i./L). According to sub-lethal tests, insecticide treatments significantly affected duration of life different, fecundity and life table parameters. The intrinsic (r) and finite (λ) rates of increase were significantly lower in insecticide treatments than that of control. Overall, results showed that thiodicarb had the highest toxicity effect on H. hebetor, while pyridalyl and chromafenozide had less adverse effects on this parasitoid. Following field experiments and subject to confirmation of the results of this study, it is possible to use pyridalil and chromafenozide in integrated pest management programs.