Study on potential effects of deltamethrin on Habrobracon hebetor Say

To clarify the potential effects of sublethal of deltamethrin on H. hebetor, the toxicity of deltamethrin to H. hebetor was determined using the residual film method, and the effects on the reproductive ability of the maternal generation and the development of its F₁ generation were further investigated. The results showed that deltamethrin treatment significantly reduced the survival rate of H. hebetor, which gradually decreased with increasing treatment time and dosage. For H. hebetor treated with sublethal dosage (LC₃₀ and LC₅₀) of deltamethrin for 2 d, the LC₅₀ treatment group exhibited the lowest female longevity (11.40 d), total fecundity (225.40 eggs), and oviposition durations (11.00 d). The paralytic ability of the H. hebetor was significantly decreased after treatment with sublethal dosages of deltamethrin, with no significant difference between the LC₃₀ and LC₅₀ treatments. The total number of paralyzed hosts of the H. hebetor decreased from 129.80 in the control group to 82.80 in the LC₃₀ treatment group and 77.60 in the LC₅₀ treatment group. The average daily number of paralyzed hosts of H. hebetor treated with sublethal dosage of deltamethrin was significantly lower than that of the control group from the 6th day of parasitism. Sublethal dosages of deltamethrin negatively affected the longevity, reproductive ability, and paralysis ability of the maternal generation of H. hebetor. No effect of sublethal dosage of deltamethrin was found on the developmental time of F₁ generation of H. hebetor. The results of this study provide reference information for the rational application of deltamethrin and the scientific release of H. hebetor for effective control of grain storage pests.