Abstract: 【Aim】This study aims to clarify the influence of multiple generations of selection with tetraniliprole on the population fitness and detoxification enzyme activities of Tuta absoluta, so as to provide a theoretical basis for the scientific and rational use of this insecticide. 【Methods】 After T. absoluta was selected with tetraniliprole for 18 generations using spraying method in the laboratory, the toxicity of tetraniliprole to the 2nd-3rd instar larvae of T. absoluta larvae in 48 h was determined by leaf-dipping method, and a tereniliprole-resistant population of T. absoluta was obtained. The fitness of the tereniliprole-resistant population of T. absoluta was evaluated by constructing the two-sex life table, and the activities of mixed-function oxidase (MFO), carboxylesterase (CarE) and glutathione S-transferase (GST) in the 2nd-3rd instar larvae were determined. 【Results】 After 18 generations of laboratory selection, T. absoluta developed 24.60-fold resistance to tetraniliprole. The larval duration, pupal duration, total preoviposition period (TPOP) and mean generation time (T) of the tetraniliprole-resistant population were all prolonged, and the 1st instar larval duration and mean generation time (T) increased significantly by 0.43 and 0.61 d, respectively, as compared to those of the tereniliprole-susceptible population. In addition, compared to the tereniliprole-susceptible population, the tereniliprole-resistant population had decreased intrinsic rate of increase (r), net reproductive rate (λ) and finite rate of increase (R₀). The tereniliprole-resistant population had a relative fitness of 0.90, indicating a survival disadvantage. The activities of GST and MFO in the 2nd-3rd instar larvae of the tereniliprole-resistant population increased significantly, being 1.25 and 1.21 times as high as those of the tereniliprole-susceptible population, respectively, while the CarE activity in the 2nd-3rd instar larvae of the tereniliprole-resistant population showed no significant change as compared with that in the tereniliprole-susceptible population. 【Conclusion】 The resistance of T. absoluta to tetraniliprole increased after selection for 18 generations in laboratory, and MFO and GST might be involved in the development of tetraniliprole resistance. The resistance of T. absoluta to tetraniliprole has a fitness cost for growth and development.

Key words: Tuta absoluta, tetraniliprole, fitness, detoxification enzyme, pesticide resistance