Bio-efficacy, persistence and residual toxicity of different insecticides against soybean leaf eating caterpillar Spodoptera litura (Fabricius) infesting soybean

Abstract

The investigations on bio-efficacy, persistence and residual toxicity of different insecticides viz., chlorantraniliprole 0.004 per cent, ethion 0.100 per cent, triazophos 0.050 per cent, indoxacarb 0.010 per cent, emamectin benzoate 0.001 per cent, quinalphos 0.050 per cent and profenophos 0.100 per cent against Spodoptera litura (Fabricius) infesting soybean were conducted at the Experimental Farm of Department of Agril. Entomology, College of Agriculture, Latur (MS) during Kharif 2015. The overall results exhibited that among the insecticide treatments, chlorantraniliprole 0.004 per cent was found to be the most effective insecticide in minimizing population of S. litura infesting soybean (0.81 larva per mrl) followed by emamectin benzoate 0.001 per cent (1.07 larvae per mrl), indoxacarb 0.010 per cent (3.27 larvae per mrl), quinalphos 0.050 per cent (3.33 larvae per mrl), profenophos 0.100 per cent (3.81 larvae per mrl), triazophos 0.050 per cent (4.11 larvae per mrl) and ethion 0.100 per cent (4.22 larvae per mrl) after application of insecticides. The maximum grain yield was obtained by the treatment with chlorantraniliprole 0.004 per cent (34.87 q per ha) while quinalphos 0.050 per cent (1:19.72) registered highest incremental cost benefit ratio. The results on residual toxicity of different insecticides against S. litura infesting soybean indicated that chlorantraniliprole 0.004 per cent and emamectin benzoate 0.001 per cent had highest persistent toxicity index (PT) (913.01 and 860.89, respectively) and LT50 values (7.59 and 6.69, respectively) against early instar larvae of S. litura after spray as compared to the other insecticides.