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

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.

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.

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.