Sublethal effect of fipronil on resistant and susceptible rice stem borer (Chilo suppressalis Walker)

The rice stem borer,Chilo suppressalis,from both resistant(Cangnan,Zhejiang)and susceptible(Taihu,Anhui)populations was treated with the respective sublethal dose(LD 10 and LD 25 )of fipronil to see if there were sublethal effects.It was found that the sublethal dose obviously depressed the survivorship,fecundity and fertility of C.suppressalis,and prolonged the larval duration.The sustained effect of fipronil on survivorship of the resistant population was stronger than that of the susceptible one.In addition,specific activity of CarE in the susceptible population increased significantly after the treatment with sublethal dose of fipronil.The K m value of CarE increased in both resistant and susceptible populations when treated with the respective sublethal dose,indicating that the affinity of CarE to α-naphthyl acetate decreased.