Toxicity and Effects of Azadirachtin, Alphacypermethrin and their Mixture on Plutella rapae L.

The toxicity of azadirachtin and alphacypermethrin to Plutella rapae L.was determined and the optimal proportion of their mixture was screened.It was found that the synergism was the most significant when the proportion of azadirachtin and alphacypermethrin was 1:1,and the co-toxicity coefficient was 187.Based on the effects and costs,2.5%mixture (1.25% azadirachtin and 1.25% alphacypermethri) was proved to be feasible.The result of field trial showed that the effect of 2.5% mixture EC was higher than 0.3% azadirachtin EC and 4.5 alphacypermethrin.