Influence of post-treatment temperature, solvents and emulsifiers on the toxicity of cypermethrin to larvae of Spodoptera litura (Fab.)

摘要

Larvae of Spodoptera litura were topically bioassayed with cypermethrin emulsion formulation and proprietary EC in combination with different solvents and emulsifiers for their toxicity at 16deg 2 and 27deg 1℃. The descending order of efficacy of the different solvents (with relative toxicity) against 9deg 1-day-old larvae was: xylene (7.41), aromex (5.54), cyclohexane (4.93), C-IX (3.93), benzene (2.40) and toluene (2.26). With emulsifier, the order was: Triton X-100 (7.41), SN4S (4.60), Teepol (2.90), Tween-80 (1.49), Swascofix DP-50 (1.28), SN4R (1.10) and S52B (1.07). However, proprietary cypermethrin EC was 2.31 times more toxic at 16deg 2 than at 27deg 1℃.