Sublethal Effects of Hexaflumuron on Adults of Apolygus lucorum (Hemiptera: Miridae)

Hexaflumuron, a benzoylurea insecticide, exhibits high toxicity against various insect pests. Sublethal doses of hexaflumuron significantly impair nymphal development and subsequent fecundity in the resulting Apolygus lucorum (Meyer-Dür) adults. However, the effects on adults of A. lucorum that are exposed to sublethal concentrations of hexaflumuron are not known. In this study, we evaluated the toxicity of hexaflumuron to 1st- and 3rd-instar nymphs, as well as one-day-old adults, of A. lucorum using an artificial diet with hexaflumuron incorporated. Acute toxicity bioassays determined the median lethal concentration (LC₅₀) for 1st- and 3rd-instar nymphs of A. lucorum to be 0.311 and 0.337 mg/L. In contrast, the LC₅₀ level for one-day-old adults of A. lucorum was 13.193 mg/L. To evaluate the sublethal effects of hexaflumuron on 3rd-instar nymphs, we used LC₁₀, LC₂₀, and LC₅₀ concentrations (0.018, 0.127, and 0.337 mg/L), fed for 48 h. The exposure of 3rd-instar nymphs to the LC₅₀ concentration significantly reduced the fecundity of adults. We also exposed one-day-old adults to LC₁₀, LC₂₀, and LC₅₀ dietary concentrations (0.089, 4.587, and 13.193 mg/L) for 48 h. Exposure to the LC₁₀ and LC₂₀ concentrations caused significant reductions in longevity and fecundity in adult females. The LC₅₀ concentration also caused a significant reduction in the longevity of adult males and the egg hatching rate. An understanding of these sublethal impacts can facilitate the development of effective control strategies targeting A. lucorum.