Relative Toxicity of Certain New Insecticides Against Spodoptera litura (Fabricius)

The relative susceptibility of 5-day old larvae of Spodoptera litura (Fabricius) to certain novel insecticides along with conventional ones was determined by bioassay using ‘Potter's tower’. On the basis of LC₅₀ value, the order of toxicity of different insecticides with relative toxicity in parenthesis was: emamectin benzoate (6.93) > fenvalerate (1.82) > indoxacarb (1.62) > cypermethrin (1.00) > abamectin (0.94) > quinalphos (0.67) > bifenthrin (0.51) > spinosad (0.44) > endosulfan (0.28) > betacyfluthrin (0.23) > lambda cyhalothrin (0.19). The relative toxicity serves as a ready reckoner for the selection of suitable insecticides for effective pest management under field conditions. Also, such baseline data would provide a record for detecting resistance level of S. litura, if any, to various insecticides at different periods.