Lethal and sublethal effects of fluralaner on Bactrocera correcta and resistance-associated impacts on development, reproduction and detoxification in a laboratory-resistant strain

The invasion, spread, and management of Bactrocera correcta have attracted considerable attention. Chemical control remains the primary approach for managing this pest. Fluralaner is a chemical agent with potential for pest control. This study elucidates the lethal and sublethal effects of fluralaner on this pest, as well as its associated impacts on a laboratory-selected resistant strain.

In this study, the survival and reproductive capacity of B. correcta exhibited concentration-dependent responses to fluralaner. At the LC₅₀, adult longevity was significantly shortened, and no viable F1 offspring were obtained. Exposure to LC₂₅ extended egg and larval periods and suppressed population growth. In the fluralaner-resistant strain, fecundity, survival rate, pupal period, pupal weight, and proportion of female offspring were significantly reduced. Furthermore, exposure to lethal and sublethal concentrations of fluralaner inhibited ovarian development and altered the titers of Vg, JH, and 20E, while GST and AChE activities were increased. Similarly, GST and AChE activities were significantly increased in the resistant strain, and the LC₅₀ was significantly reduced when fluralaner was combined with the synergist DEM. These findings suggest that detoxification enzymes are involved in the development of fluralaner resistance in B. correcta.

Overall, fluralaner exhibited strong toxicity against B. correcta, and resistance development was accompanied by adaptive detoxification responses. These findings provide a basis for the potential use of fluralaner as a chemical agent for tephritid fruit fly control, and lay a foundation for future field application, as well as for further mechanistic studies on the detoxification metabolism of isoxazoline insecticides. © 2026 Society of Chemical Industry.