Lethal and sublethal effects of fluralaner on the citrus red mite, Panonychus citri (McGregor)

The citrus red mite, Panonychus citri (McGregor) is a globally distributed agricultural pest. Of late, resistance to common acaricides has raised concerns that chemical control of P. citri is an inefficient means of control. Fluralaner, a highly toxic isoxazoline insecticide used to treat various ectoparasites, presents one potential alternative. However, little information has been reported about the effect of fluralaner on the citrus red mite. This study aims to evaluate the toxicity, sublethal and transgenerational effects of fluralaner on P. citri.

In both laboratory and field populations of P. citri, we found fluralaner to be more toxic than conventional alternatives, including fenpropathrin, bifenazate, azocyclotin and chlorpyrifos. Interestingly, fluralaner proved more toxic to female adults than to the eggs of P. citri, with median lethal concentrations (LC₅₀) of 2.446 and 122.7 mg L^-1, respectively. Exposure to sublethal concentrations of fluralaner (LC₁₀, LC₂₀ and LC₃₀) significantly reduced the fecundity and longevity of female adults P. citri individuals. Although concentrations of fluralaner applied to the parental female adults (F₀) led to some changes in the developmental parameters, there were no significant changes in most of the life table parameters or population growth of the F₁ generation.

Our results indicate that fluralaner is highly toxic to P. citri, and a significant sublethal effect on F₀ could suppress the population growth of P. citri, but not for F₁. Fluralaner may be considered as a pesticide for the future management of the citrus red mite. © 2024 Society of Chemical Industry.