Abstract: 【Aim】 To clarify the optimum period for Aphis gossypii control in the field, and the effects of sublethal concentrations of flonicamid on the growth, development and reproduction of A. gossypii on Zanthoxylum bungeanum. 【Methods】 The sublethal concentrations of flonicamid against the adults and different instar nymphs of A. gossypii were determined with leaf-dipping method by laboratory toxicity assay, and the effects of sublethal concentrations (LC₁₀ and LC₃₀) of flonicamid on the adult longevity and fecundity of A. gossypii parents (F₀) and their F₁ offspring were measured in 24 h by leaf-dipping method, and the life table parameters such as the net reproductive rate, mean generation time, intrinsic rate of increase, finite rate of increase, and population doubling time of the F₀ and the F₁ generations were calculated. 【Results】 The sublethal concentrations of flonicamid increased with the developmental stage of A. gossypii. The LC₃₀ values of flonicamid against the 1st-4th instar nymphs and adults in 24 h were 22.939, 26.346, 36.050, 36.531 and 36.911 mg/L, respectively. Exposure of A. gossypii adults to both LC₃₀ and LC₁₀ of flonicamid could reduce the female adult longevity and number of eggs laid per female of the F₀ and F₁ generations of A. gossypii. The female adult longevity of the F₀ generation of A. gossypii in the treatment group with LC₃₀ of flonicamid was (6.15±0.45) d, which was significantly shorter than that in the control group treated with clean water ［(8.53±0.39) d］, and the number of eggs laid per female in the treatment group with LC₃₀ of flonicamid was 9.53±0.44, which was significantly less than that in the control group (25.08±0.61). The female adult longevity of the F₁ generation of A. gossypii in the treatment group with LC₃₀ of flonicamid was (9.06±0.44) d, which was significantly shorter than that in the control group ［(10.85±0.52) d］, and the number of eggs laid per female in the treatment group with LC₃₀ of flonicamid was 15.76±0.40, which was significantly less than that in the control group (28.06±0.45). The female adult longevity of the F₀ generation of A. gossypii in the treatment group with LC₁₀ of flonicamid was (7.45±0.37) d, showing no significant difference from that in the control group ［(8.53±0.39) d］, and the number of eggs laid per female in the treatment group with LC₁₀ of flonicamid was 17.56±0.56, which was significantly less than that in the control group (25.08±0.61). In the treatment group with LC₁₀ of flonicamid, the female adult longevity of the F₁ generation of A. gossypii was (10.10±0.51) d, showing no significant change from that in the control group ［(10.85±0.52) d］, and the number of eggs laid per female was 22.40±0.45, which was significantly less than that in the control group (28.06±0.45). The net reproductive rates of the F₀ and F₁ generations of A. gossypii in the treatment group with LC₃₀ of flonicamid were 7.83±0.39 and 15.22±0.43, respectively, which were significantly lower than those in the control group (22.57±0.64 and 23.87±1.25, respectively), and the finite rates of increase of the F₀ and F₁ generations of A. gossypii in the treatment group with LC₃₀ of flonicamid were (1.83±0.12) and (1.65±0.06) d^-1, respectively, which were significantly lower than those in the control group ［(1.97±0.29) and (1.69±0.17) d^-1, respectively］, and the net reproductive rates of the F₀ and F₁ generations of A. gossypii in the treatment group with LC₁₀ of flonicamid were 15.17±0.46 and 18.65±0.55, respectively, which were significantly lower than those in the control group (22.57±0.64 and 23.87±1.25, respectively), and the mean generation time of the F₀ generation of A. gossypii in the treatment group with LC₃₀ of flonicamid was (3.41±0.17) d, which was significantly lower than that in the control group ［(4.61±0.21) d］, and the intrinsic rate of increase of the F₀ generation of A. gossypii in the treatment group with LC₃₀ of flonicamid was (0.60±0.23) d^-1, significantly lower than that in the control group ［(0.68±0.17) d^-1］. 【Conclusion】 Flonicamid showed good control efficacy on the A. gossypii population, especially on A. gossypii at the early developmental stage, and sublethal concentrations of flonicamid inhibited the growth, development and reproduction of the F₀ and F₁ generations of A. gossypii. This study provides a theoretical basis for the rational use of flonicamid in the control of A. gossypii on Z. bungeanum.

Key words: Aphis gossypii, flonicamid, sublethal effect, growth and development, life table parameter