Cytochrome P450 monooxygenses have been proven to be associated with high resistance in Bemisia tabaci B(Middle East-Minor Asia 1 genetic group)and Q(Mediterranean genetic group)biotypes to neonicotinoid class of insecticides.In this study,the RNA interference(RNAi)effects on P450 CYP6CM1 gene expression,mortality,and pesticide-detoxifying ability between B.tabaci B and Q biotypes were compared in an attempt to provide basis for potential RNAi application in management of this pest.Double-stranded RNAs(dsRNA)of P450 CYP6CM1 genes corresponding to the B and Q biotypes were synthesized using specific primers and introduced into the insect body of B.tabaci adults through feeding.The results showed that dsRNA significantly silenced the target genes with dsRNA concentration or treatment time,and silencing was more effectively in B biotype than in Q biotype.Feeding dsRNA led to the high mortality in both biotypes,with higher mortality in biotype B(up to 85.88%)than in biotype Q(up to 56.40%).In addition,ability in detoxifying imidacloprid and nicotine was inhibited in dsRNA-treated adults of both biotypes,more efficiently in biotype B than in biotype Q.In conclusion,RNA interference of P450 CYP6CM1 gene decreased gene expression,increased mortality,inhibited ability to detoxify pesticide or plant secondary metabolite in both biotypes of B.tabaci,with better efficacy in biotype B than in biotype Q.