1Department of Entomology, CCS Haryana Agricultural University, Hisar-125 004, Haryana (India).
2Division of Entomology, Indian Agricultural Research Institute, New Delhi-110 012 (India).
The efficacy of cypermethrin emulsion formulated separately with mixtures of solvents (1:1), viz., xylene + aromex or xylene + toluene, using either Triton X-100 or Tween-80 as emulsifiers; and mixtures of emulsifiers (1:1), viz., Triton X-100 + Tween-80, Triton X-100 + Swascofix DP-50 or Triton X-100 + Teepol, using either aromex or xylene as solvents, was studied against the third instar larvae of Spodoptera litura (Fab.). The toxicity of each of the emulsion formulation was compared with proprietary cypermethrin emulsion concentrate. The most effective formulation was based on solvent mixture (xylene + aromex) with emulsifier Tween-80, the LC50 being 0.000229. Also, when the same solvent mixture was formulated with Triton X-100 and Tween-80 separately, the latter emulsifier produced more pronounced effect on the toxicity of mixture in comparison to Triton X-100. The solvent mixture (xylene + toluene) was more effective than their individual solvent combination with Tween-40 and proprietary product. With aromex as solvent, the emulsifier mixtures, viz., aromex + (Triton X-100 + Swascofix DP-SO), aromex + Triton X-100 and aromex + Swascofix DP-50 were 2.80, 0.42 and 8.94 times, respectively, as effective as proprietary cypermethrin. With xylene as solvent, the formulation containing emulsifier mixtures, viz., Triton X-100 + Tween-80, Triton X-100 + Swascofix DP-50, and Triton X-100 + Teepol were 9.91, 10.94 and 2.65 times more effective than the proprietary cypermethrin.
