Abstract: 【Aim】 The western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important invasive insect pest. It is also the most effective vector for tomato spotted wilt virus (TSWV) which has a certain influence on the growth and development of F. occidentalis. Spinosad is one of the most effective insecticides in F. occidentalis control. However, it has been reported that F. occidentalis has developed resistance to spinosad in the field. Whether TSWV has an impact on the resistant strain and how high the impact is are not clear. This study would provide a basis for further understanding of the impact of TSWV on F. occidentalis.【Methods】 Age-stage and two-sex life tables were used to study the biological characteristics of the spinosad-resistant and susceptible strains of F. occidentalis with TSWV treated or nontreated. The susceptibilities of the spinosad-resistant and susceptible strains of F. occidentalis to three insecticides (spinosad, emamectin benzoate and chlorfenapyr) were investigated by using leaf-tube residue method. 【Results】 For the resistant strain of F. occidentalis treated by TSWV, the developmental period shortened, the female longevity and fecundity increased, but they showed no significant difference from those of the non-treated thrips (P>0.05). The intrinsic rate of increase (r, 0.0433 d^-1) and the net reproduction rate (R₀, 2.210) of the resistant strain treated by TSWV were significantly higher than those in the control group (0.0356 d^-1 and 1.972, respectively) (P≤0.001). As for the susceptible strain treated by TSWV, the developmental period shortened, the adult longevity increased significantly (P≤0.001), and the fecundity increased as well. The R₀ of TSWV-treated susceptible strain (4.125 ) was significantly higher than that in the control group (3.979 ) (P≤ 0.001). The susceptibilities of the spinosad-resistant and susceptible strains of F. occidentalis treated by TSWV to spinosad had no obvious change compared with those of the corresponding nontreated thrips. However, their susceptibilities to emamectin benzoate and chlorfenapyr decreased significantly. 【Conclusion】 TSWV has directly positive effect on the biological characteristics of both the spinosadresistant and susceptible strains of F. occidentalis. The TSWV treated thrips have shortened developmental period, enhanced fecundity and longer adult longevity, and decreased susceptibility to insecticides.

Key words: Frankliniella occidentalis, tomato spotted wilt virus, spinosad, resistance, life table, insecticide susceptibility