Relative Toxicity of Imidacloprid and Bifenthrin against Lipaphis Erysimi (Kalt.)

The relative toxicity of imidacloprid and bifenthrin were evaluated against the 4^th instar nymph of Lipaphis erysimi (Kalt.) by working out the probit analysis. Imidacloprid was found to be most effective followed by bifenthrin and deltamethrin. Their LC₅₀ values were 0.00017 and 0.00015 for imidacloprid, 0.00152 and 0.00122 for bifenthrin, 0.00199 and 0.00134 for deltamethrin, after 24 and 48 h of treatment respectively. Imidacloprid was 8.93 times and bifenthrin 1.10 times more toxic than deltamethrin after 48 h of treatment. On the basis of LC₅₀ values the order of toxicity was found to be imidacloprid >bifenthrin >deltamethrin.