Cross-resistance and the underlying mechanisms of clothianidin resistant population of Frankliniella occidentalis to insecticides

Clothianidin, belonging to neonicotinoid insecticide with systemic and contact mechanisms, is used to control the invasive pest . To identify the resistance risk, we examined the cross-resistance to multiple insecticides and mechanisms of clothianidin resistant population of . The results showed that developed a high level of resis-tance to clothianidin (56.8-fold) after selecting for 45 generations. The resistant population of had medium level of cross-resistance to thiamethoxam, imidacloprid, chlorpyrifos, cyhalothrin and emamectin benzoate (18.6>RR >11.3), and the low level of cross-resistance to phoxim and methomyl, but no cross-resistance to chlorfenapyr and spinosad. The synergists piperonyl butoxide (PBO) and triphenyl phosphate (TPP) had significant synergistic effects on clothianidin in killing the resistant population (CL), Yunnan wild population (YN) and susceptible population (S). Compared with the sensitive population, the CL populations had significantly increased activities of mixed-functional