Study on Toxicities and Control Effect of Different Bio-Insecticides on Aphis gossypii Clover

The efficacy test of the four kinds of bio-Insecticides was carried out to control Aphis gossypii Glover in the field.The toxicity of four kinds of bio-insecticides to A.gossypii Glover was determined with micro-drop method and immension method.The results showed that the effects of 2% Avermectin(EC) with 1000 fold,and 0.3% Azadirachtin(EC) with 1000 fold were quick and persistent.The control effect obtained from field tests had been kept by 97.32% and 88.22% after 7 days.The toxicity of Avermectin to A.gossypii on the LD50 and LD90 with immertion method were 0.099 5,3.344 9 μg/g,Azadirachtin was 0.056 1,0.157 5 μg/g.The toxicity of Avermectin to A.gossypii on the LC50 and LC90 with immertion method were 24.677 6,32.695 0 μg/g,Azadirachtin was 0.295 9,1.021 8 μg/g.Avermectin and Azadirachtin would be applied to control population of cotton aphid.