Sublethal Effects of Some Conventional and Biorational Insecticides on Ectoparasitoid, Habrobracon hebetor Say (Hymenoptera: Braconidae)

摘要

This study was carried out to assess the effects of sublethal dose of profenofos, spinosad, thiodicarb and field recommended dose of hexaflumuron on demographic and biological parameters of H. hebetor . Gross reproductive rate in control (68.87) was significantly higher than insecticide treatments. The highest and the lowest gross reproductive rate between insecticides were related to the profenofos and spinosad, respectively. Higher intrinsic rat of increase in control (0.17) compared with insecticide treatments indicated harmful effects of insecticides on it. Hexaflumuron and spinosad had the highest (0.15) and the lowest (0.1) intrinsic rate of increase between insecticides, respectively. Number of laid eggs was significantly affected by insecticides and it was approximately 2 times more than insecticide treatments in control. In this study, hexaflumuron had tremendous sublethal negative effects on biological parameters of H. hebetor with no lethal effects on adult wasps. The female longevity in control (29.41) had no significant difference with the means of profenofos and hexaflumuron, but differences between spinosad and thiodicarb with control was significant. Spinosad had the lowest longevity (12.79). However hexaflumuron, profenofos and spinosad had lower generation time compared with control and thiodicarb but differences between treatments were not significant. Sex ratio of H. hebetor offsprings was significantly affected by insecticides. In control, it was lowest (39.23) which indicated that proportion of female to male was highest ( ≈ 2 time) and it was highest in spinosad (54.94) which means that spinosad caused higher male production in population. In all treatments, especially spinosad and thiodicarb, increase in female age caused increase in male production.