Toxicity of Some Insecticides to the Fall Army Worm Spodoptera Frugiperda

A laboratory bioassay (topical application) was conducted to evaluate the relative toxicity of ten insecticides against third instar larvae of fall army worm, Spodoptera frugiperda (J E Smith). Emamectin benzoate was found to be the most toxic with least LC₅₀ value (1 ppm). The order of toxicity was emamectin benzoate (1 ppm)> spinetoram (1.2 ppm)> chlorantraniliprole (1.8 ppm)> novaluron+ emamectin benzoate (7.7 ppm)> novaluron (18 ppm)> novaluron+ indoxacarb (31.7 ppm)> flubendiamide (33.8 ppm)> indoxacarb (42.3 ppm)> lambda-cyhalothrin (77.2 ppm)> chlorpyriphos (184.7 ppm). Emamectin benzoate, spinetoram, chlorantraniliprole, novaluron+ emamectin benzoate, novaluron, novaluron+ indoxacarb, flubendiamide, indoxacarb and lambda-cyhalothrin showed 184.70, 153.92, 102.61, 23.99, 10.26, 5.83, 5.46, 4.37 and 2.39 folds toxicity over chlorpyriphos, respectively at 72 hr after treatment.