STUDIES ON THE POPULATION COMPONENTS OF APHIS GOSSYPII GLOVER IN HENAN PROVINCE WITH CHROMOSOME ANALYSIS Resistance selection and resistance stability by several insecticides to Aphis gossypii Glover Establishment and development of web database for cotton aphid prediction Microsatellite primer-PCR studies on the population differentiation of Aphis gossypii in relation to host plants and seasons The structure and dynamics of natural enemy community and controlling effect against Aphis gossypii in cotton-alfalfa intercrop fields