Sublethal and transgenerational effects of broflanilide on the citrus red mite, Panonychus citri.

Background: The citrus red mite, Panonychus citri is a serious pest of the citrus industry and has developed resistance to many acaricides. Broflanilide is a novel meta-diamide insecticide that binds to a new site on the γ -aminobutyric acid receptor with high potency against pests. However, little information has been reported about its effect on the citrus red mite.

Results: Broflanilide exhibited higher toxicity to female adults and eggs of a laboratory strain of P. citri The median lethal concentration (LC₅₀), 9.769 mg/L and 4.576 mg/L, respectively) than other commonly used acaricides and was also toxic to two P. citri field strains. Broflanilide treatment with LC₁₀, LC₂₀, and LC₃₀ significantly decreased the fecundity and longevity of female adults of F₀ P. citri compared with the control. The duration of larva, protonymph, deutonymph and adult, and total life span in the F₁ generation were significantly reduced after treatment of F₀ with broflanilide. Population parameters, including the intrinsic rate of increase (r) and finite rate of increase (λ), were significantly increased, and the mean generation time (T) of F₁ progeny was significantly reduced in the LC₂₀ treatment. The predicted population size of F₁ increased when parental female adults were treated with sublethal concentrations.

Conclusion: Broflanilide had high acaricidal activity toward P. citri, and exposure to a sublethal concentration significantly inhibited the population growth of F₀. The transgenerational hormesis effect is likely to cause population expansion of F₁. More attention should be paid when broflanilide is applied to control P. citri in citrus orchards. © 2024 Society of Chemical Industry.