Abstract: Studies on the relationship between A.ignotum population density and main ecological factors in cotton fields show that the population density is positively related to the lasted years of continuous cropping, but negatively related to the altitude and underground water level.The mite density in open cotton fields is significantly higher than that in mulched ones. The floating time of nymph in static water can be lasted 5.2 hours.For the eviposition of adults,the optimum soil moisture content is 12.5%.The killing power of different insecticides and their applicaition ways to larvae is in the order of spraying decamethrin>spraying omethoate>spraying dicofol>painting slow-releasing methoate on the stem.Developing irrigated cotton field.properly prolonging the lasted years of continuous cropping of cotton,and painting cottop stem during its growing period with insecticide to control aphid will have an important role in increasing A.ignotum population density.

Key words: Allothrombium ignotum, Population density, Eec-environment, dimethyl disulfide, slow-release system, Apolygus lucorum, repellent, behavioral manipulation