Abstract: In the laboratory tests conducted during 1992 1993,an Entomophthora 1∶150 prep aration was sprayed against Hyalopteus arundinis on peach trees and Aphis gossypii and Aphis citricola on pomegranate.A 1∶200 preparation was spray ed against Myzus persicae on apple trees.The control effect after 24 hr was 97%,66.8%,84% and 92%,respectively.In the field trials,the control effects of 1 ∶100,1∶150 and 1∶200 preparations against M.persicae were all at 99%.But the aphid population in the plot treated with the 1∶200 preparation increased d ramatically 96 hr after the treatment.Large scale field trials were conducted wi th 1∶200,1∶400 and 1∶600 preparations against M.persicae in apple orchard s.The control effect was 94.9% 98.1%,and the aphid population did not resurge i n 10 days after the treatment.In contrast the aphid population in the nontreated check orchard increased by 474%