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The predatory gall midge, Aphidoletes aphidimyza(Rondani), and tobacco aphid cocoon wasp, Aphidius gifuensisAshmead, are important natural enemies of Myzus persicae(Sulzer) (Hemiptera: Aphididae). Predation by A. aphidimyzaand A. gifuensiscan regulate M. persicae; however, how interspecific interference competition affects their foraging efficiency is unknown. Here, we investigated the consumption and parasitization abilities of A. aphidimyza3rd instar larva and A. gifuensisadults under various conditions. Consumption of parasitized aphids by A. aphidimyza3rd instar larvae was significantly lower than that of nonparasitized controls, with a substantial increase in handling time. The presence of A. gifuensisadults did not significantly affect the predation capacity of A. aphidimyzalarvae. Relative to controls, A. aphidimyzalarvae predation trace (PT) and imago activity significantly decreased A. gifuensisparasitism rates at different aphid densities. Further, A. aphidimyzalarvae PT increased the A. gifuensishandling time of M. persicae, whereas the presence of A. aphidimyzaadults had the opposite effect. Coexistence with heterospecific natural enemies reduced the parasitic capacity of A. gifuensis, whereas A. aphidimyzalarvae predation capability was influenced to a lesser extent. Our results demonstrate that intraguild interactions strongly influence the predatory and parasitic efficacy of A. aphidimyzaand A. gifuensis, although the effect on A. gifuensiswas more pronounced. For effective biological control of M. persicaeusing A. aphidimyzaand A. gifuensis, we recommend releasing A. aphidimyzafirst to mitigate intraguild predation and enhance the overall success of the pest control program.

Habrobracon hebetor(Say) (Hymenoptera: Braconidae) is a cosmopolitan, idiobiont, and gregarious ectoparasitoid, which can parasitize the larvae of several pyralid and noctuid moths. However, adult parasitoids require cold storage to ensure that adequate individuals are available when a pest outbreak occurs. To understand the effects of cold storage after acclimation on offspring fitness of H. hebetor, the development, fecundity, population parameters, and paralysis rate of the F1generation were evaluated using an age–stage, two-sex life table. Four pairing treatments were used in this study, with refrigerated males and females (ReF×ReM), unrefrigerated females and refrigerated males (UnF×ReM), refrigerated females and unrefrigerated males (ReF×UnM), and unrefrigerated females and males (UnF×UnM, control). Cold storage after acclimation had no significant effect on the fecundity or oviposition period of F0-generation H. hebetor. Moreover, the survival rate (Sa= 61.43%), proportion of females (Nf/N= 0.41), intrinsic rate of increase (r= 0.3450), finite rate of increase (λ= 1.4121), net reproduction rate (R0= 149.47), and net paralysis rate (C0= 74.52) of ReF×UnM and UnF×UnM (Sa= 50.00%, Nf/N= 0.34, r= 0.3297, λ= 1.3881, R0= 155.69, C0= 62.90, respectively) treatments were significantly higher than those of the ReF×ReM treatment (Sa= 45%, Nf/N= 0.16, r= 0.2277, λ= 1.2558, R0= 68.81, C0= 31.61, respectively) (except for the Saof UnF×UnM treatment), and there was no significant difference between the 2 treatments. Overall, it is advisable to avoid simultaneous cold storage of female and male parasitoids or to add unrefrigerated males appropriately when using cold-stored parasitoids to control pests.

Habrobracon hebetor(Say) is an important biological control agent for lepidopteran pests of stored products. In this study, the age-specific functional response, paralysis rate, and parasitism rate of H. hebetorunder different host deprivation treatments (PC: without host deprivation, used as the control, P1d: host deprivation, but the host was removed after 1 d contact, and PW: host deprivation from beginning) were evaluated at different larval densities (5, 10, 20, 40, and 80) of the Ephestia elutella(Hübner) at 28 ± 1°C, 75 ± 5% RH and 16:8 h L:D. Ages of parasitoid females used were 2, 5, 10, and 20 d old. The logistic regression results indicated that the functional response of H. hebetorfemales under different host deprivation treatments was type II. The longest handling time was observed in 20-d old females, while the shortest handling time and highest maximum attack rate (T/Th) were estimated at the age of 2 d in all treatments. The paralysis and parasitism rates of H. hebetorwere the highest at 2, 5, and 10-d old in all treatments. The results of this study suggest that H. hebetorfemales up to 10-d old can be used as an efficient biological control agent against E. elutella. The data of this study can also be used to predict the efficacy of different aged H. hebetorfemales in controlling E. elutellapopulations.