Adverse impacts of development on the deltamethrin-exposed host Ephestia elutella (Lepidoptera: Pyralidae) on population parameters of Habrobracon hebetor (Hymenoptera: Braconidae)

Abstract

Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is a widely distributed parasitoid that can be used to control numerous lepidopteran pests including Ephestia elutella (Hübner) (Lepidoptera: Pyralidae). The present study was aimed to evaluate the indirect impacts of deltamethrin on the life table parameters and the paralysis rate parameters of H. hebetor using the age-stage, two-sex life table method under laboratory conditions. The results indicated that the preadult survival rate of H. hebetor was significantly reduced (with LC5 and LC10 values of 0.41 and 0.49, respectively) in insecticide-treated populations. Similarly, after low-concentration (LC5 and LC10) treatments with the insecticide, the values of three important life table parameters (i.e., intrinsic rate of increase [r], finite rate of increase [λ], and net reproductive rate [R0]), and two major paralysis rate parameters (i.e., net paralysis rate [C0], and finite paralysis rate [ω]) of H. hebetor were significantly decreased compared to the control group. However, these parameters were not significantly different between the LC5 and LC10 treatment groups. Our results demonstrated that low lethal concentrations of deltamethrin can significantly depress the performance of H. hebetor. In order to establish an effective integrated pest management program to control E. elutella, it will be necessary to determine the adverse effects of deltamethrin on H. hebetor under warehouse conditions.