The resistance of Brassica chinensis to the turnip aphid was evaluated by using the seedling bulk screening test in the greenhouse and the field.Among the 19 varieties (lines) tested,Jinbianbai and Shanghaibai were resistant.When the aphids fed on these,they showed lower food uptake and fecundity,slower development,and smaller population growth as compared to when they fed on the susceptible varieties,indicating the presence of antibiotic factors.Also the aphid-resistant varieties exhibited resistance to the mosaic virus disease.