Abstract: To find the essential oils with high insecticidal activity and promote the development of hygienic insecticides, essential oils from 41 plants belonging to 17 families were evaluated for adulticidal activity against female adults of Culex pipiens pallens by airtight fumigation in conical flask and hermetic round canister method. The results showed that 26 essential oils (12 μL/L) including spearmint oil, lavender oil and Litsea cubeba oil were very toxic to the mosquito (KT₅₀<15 min) by airtight fumigation in conical flask. Further assay using hermetic round canister method indicated that 5 essential oils (wintergreen oil, blumea oil, peppermint oil, Eucalyptus robusta oil and E. globulus oil) had high fumigation toxicity at the concentration of 10 μL/L, and their KT₅₀ values were 16.91, 21.20, 22.57, 18.43 and 19.48 min, respectively. The results demonstrate that wintergreen oil, blumea oil, peppermint oil, E. robusta oil and E. globulus oil all have high fumigation activity against C. pipiens pallens, with the potential to be developed as hygienic insecticides

Key words: Culex pipiens pallens, essential oil, fumigation activity, hygienic insecticide, median knockdown time (KT₅₀)