The Effect Of Pesticides On Eretmocerus Hayati(Hymenoptera:Aphelinidae) In Xinjiang

The pesticides tolerence of Eretmocerus hayati,a dominant parasitoid of Bemisia tabaci in Xinjiang,was studied in laboratory and field.The main results are as follows:1.The toxicity tests showed that only abamectin exhibited weaker toxicity to E.hayati than that of B.tabaci?37 fold?in our insecticide test group,but all of the other 9 pesticides showed stronger toxicity to E.hayati than that of B.tabaci.Meanwhile,the order of resistance of 10 insecticides to Eretmocerus hayati was:avermectin<spinetoram<spinosad<beta cypermethrin<lambda-cyhalothrin<acetamiprid<imidacloprid<thiamethoxam<sulfoxaflor<chlorpyrifos.2.In the comparisons of 10 insecticides effects on the parasitism rate and eclosion rate of Eretmocerus hayati under LC₃₀ and LC₅₀ concentration,it suggested that chlorpyrifos,avermectin and lambda-cyhalothrin had the greatest impact on the eclosion rate of Eretmocerus hayati,and 0.69-0.78 times and 0.72-0.78 times over the control under the concentration of LC₃₀ and LC₅₀,respectively.Meanwhile,thiamethoxam had the minimal impact,0.97 and 0.98 times over the control under LC₃₀ and LC₅₀concentration,respectively.However,there was no significant difference among the 10 insecticides.Among the 10 insecticides,sulfoxaflor and lambda-cyhalothrin had the greatest influence on the parasitism rate under LC₃₀ and LC₅₀ concentration,0.6 and 0.62 times of the control,respectively.3.Indoor simulated fumigation results showed that the toxicity of two smoke fumigants on Eretmocerus hayati was evidently stronger than that to Bemisia tabaci.But there waere no significant differences between both agents and two methods used in the experiment.Furthermore,greenhouse fumigation test indicated that the corrected decrease rate reached 100%,indicating that the application of smoke fumigant was not conducive to the protection and utilization of Eretmocerus hayati.4.Based on the field experiment,all of tested 10 pesticides showed low efficacy against B.tabaci adults,only the control effect of chlorpyrifos reached to 84.63% after the treatment of 3d,however the efficacy against B.tabaci larvae,beta-cypermethrin,abamectin and Sulfoxaflor showed better effect at 84.75%-93.95% after the treatment of 7d.Very stronger toxic action were investigated for all of tested 10 pesticides,the mortalities of abamectin,spinosad,spinetoram and beta-cypermethrin reached to 86.97-89.45% after the treatment of 7d,and the mortalities of the others were all over 90%,the mortalities of both chlorpyrifos and cyhalothrin were up to 98%.