关键词: 茶银尺蠖, 茚虫威, 亚致死效应, 发育抑制, 产卵量, 室内毒力

Abstract: To elucidate the sublethal effects of indoxacarb on Scopula subpunctaria and their impact on population growth，the laboratory toxicity of 15% indoxacarb suspension concentrate（SC）against the 3rd⁃ and 5th⁃instar larvae was assessed using the leaf⁃dipping method. The sublethal concentrations LC₅，LC₁₅，and LC₂₅ were determined，and the changes in larval development，adult longevity，and reproductive parameters following treatment with these concentrations were observed. The results indicated that indoxacarb was more toxic to 3rd⁃instar larvae than to 5th⁃instar larvae. At 72 h post⁃treatment，the LC₅₀，LC₂₅，and LC₁₅ for 5th⁃instar larvae were 2 704.21，167.26，and 37.57 mg/L，corresponding to 6.71，2.72，and 1. 68 times those for 3rd⁃instar larvae，respectively，whereas the LC₅ for 5th⁃instar larvae was only 74.39% of that for 3rd⁃instar larvae. The 5th⁃instar⁃to⁃pupation period was significantly prolonged by 2.9 d at LC₂₅，whereas sublethal concentrations did not significantly affect pupal duration. Sublethal treatments shortened the adult longevity of both females and males to varying degrees，with the most significant reduction（16.53 d）observed in female adults derived from 5th⁃instar larvae treated with LC₂₅. Only the LC₁₅ treatment of 5th⁃instar larvae significantly extended the pre⁃oviposition period by approximately 2.87 days. All three sublethal concentrations significantly shortened the oviposition period by 5.07—13.07 days across both instar treatments，and in the 5th⁃instar larval treatments，the post⁃oviposition period was significantly reduced by 2.73—4.33 days. All sublethal treatments significantly reduced the fecundity per female. Compared with the control，the fecundity per female under LC₂₅ treatment decreased by 91.31% in the 3rd⁃instar group and 95.73% in the 5th⁃instar group. In summary，sublethal concentrations of indoxacarb can effectively suppress the population growth potential of S.subpunctaria by inhibiting adult longevity and reproductive capacity.Thus，indoxacarb is a suitable agent for green control in tea plantations，and should be applied rationally during the early larval stages with due attention to resistance management.

Key words: Scopula subpunctaria, Indoxacarb, Sublethal effect, Developmental inhibition, Fecundity, Laboratory toxicity