Reproductive and detoxifying responses of Panonychus citri (Acari: Tetranychidae) to sulfoxaflor stress

Panonychus citri, is a destructive pest in citrus orchards. The diversity of pests in citrus orchards leads to the improper pesticides application, and induced resistance may be an alternative mechanism for pest resurgence. In the present study, the acute toxicity of sulfoxaflor against P. citri adult females in leaf-dipping exposure experiment was determined at 24 h. Furthermore, the effects of sublethal (LC30) and lethal (LC50) concentrations of sulfoxaflor by the age-stage, two-sex life table approach were elucidated and these results revealed that the pre-adult period and the longevity of P. citri in the F1 generation were decreased. Additionally, the fecundity, R0 and r was significantly increased in the LC30- treated group, while the fecundity, R0 and λ of LC50- treated group was decreased significantly. Furthermore, the mRNA expression levels and activities of vitellogenin (Vg), vitellogenin receptor (VgR), carboxylesterases (CarE), glutathione-S-transferases (GST), and cytochrome P450 monooxygenases (CYP450) were significantly different at the sulfoxaflor treatments as compared to the control. Importantly, silencing of the CYP392B6 gene by RNA interference altered adult females of P. citri sensitivity towards sulfoxaflor and resulted in a significant increase in CYP450 content. Therefore, all these results in this study will contribute to a comprehensive risk assessment of sulfoxaflor on P. citri resurgence and will provide a convincing reference for the understanding of the mechanisms of fecundity and metabolic resistance to sulfoxaflor.