Lethal and sublethal toxicity of some plant-derived essential oils in ectoparasitoid wasp, Habrobracon hebetor Say (Hymenoptera: Braconidae)

Habrobracon hebetor Say is among the most efficient natural enemies of several lepidopteran insect pests. In the present study, the lethal and sublethal activities of essential oils isolated from aromatic plants Achillea millefolium L., Foeniculum vulgare Mill, Ocimum basilicum L., and Zataria multiflora Boiss were studied on the H. hebetor female wasps. A. millefolium and Z. multiflora essential oils with lower LC 50 values displayed lower toxicity on parasitoid wasps than F. vulgare and O. basilicum essential oils. Although LC 30 values of essential oils affected the fecundity and fertility of treated wasps, A. millefolium and Z. multiflora essential oils were harmless than F. vulgare and O. basilicum oils. The lowest r m (intrinsic rate of increase), R 0 (net reproductive rate), GRR (Gross reproductive rate), and λ (Finite rate of increase) values (0.20 day, 16.13 offspring, 83.61 egg, and 1.24 day, respectively) distinguished on female wasps treated by F. vulgare essential oil. Based on the results of present study, A. millefolium and Z. multiflora essential oils indicated lower lethal and sublethal effects on the H. hebetor than F. vulgare and O. basilicum essential oils, and therefore, they can be considered as relatively safe agents to H. hebetor in the management of its lepidopteran insect pests.