Toxicity of synthetic pyrethroids against Spodoptera mauritia found attacking maize in the farmers’ fields

The contact toxicity of three synthetic pyrethroids viz., deltamethrin, alphamethrin and bifenthrin was investigated against third instar of swarming caterpillar, Spodoptera mauritia by dry film technique and topical application technique. The data on mortality were recorded twenty-four hours after setting the experiment. The order for toxicity of different synthetic pyrethroids, based on LC₅₀/LD₅₀ Value was: Deltamethrin > bifenthrin > Alphamethrin. On the basis present findings Deltamethrin was found to be most suitable synthetic pyrethroid and was more effective even at low LC₅₀/LD₅₀ value.