Toxicity and Sublethal Effects of Lambda-Cyhalothrin Insecticide on Parent and Filial Generations of Henosepilachna vigintioctomaculata (Coleoptera: Coccinellidae)

Lambda-cyhalothrin is a synthetic pyrethroid insecticide that is widely used to control leaf-eating pests. Because of increased insecticide resistance, an understanding of sublethal cross-generational effects of insecticides is important. We examine the effects of sublethal concentrations (SLCs) (LC10, LC20, and LC40) of lambda-cyhalothrin on the growth, reproduction, and detoxification enzyme activities of F0 and F1 generation Henosepilachna vigintioctomaculata. Lambda-cyhalothrin is toxic to adult H. vigintioctomaculata, with an LC40 at 48 h of 0.355 mg L−1. At SLCs, lambda-cyhalothrin significantly reduces the longevity and average fecundity of F0 and F1 adults, and prolongs the durations of the egg, larval, and pupal stages and adult preoviposition period. Additionally, an increased lambda-cyhalothrin concentration significantly decreases net reproductive rates, and both finite and intrinsic rates of increase in the F1 generation, and significantly increases the average generation cycle. The detoxification enzyme activity of F1 adults treated with SLCs of lambda-cyhalothrin for 48 h trends upwards. Results indicate that low concentrations of lambda-cyhalothrin induce glutathione S-transferase and carboxylesterase activities and inhibit multifunctional oxidase activity. The growth, development, and reproduction of the H. viltioctomaculata F1 population remain inhibited by lambda-cyhalothrin treatment in the adult stage, and inhibitory effects increase with increased lambda-cyhalothrin concentration. The control efficacy of lambda-cyhalothrin against H. viltioctomaculata shows cross-generational effects.