Abstract: The mosaic control with insecticides seems not suitable for insects such as aphids which reproduce by parthenogenesis and have low mobility in apterous form. In the present study we adopted another strategy by spraying unrelated insecticides at first and then exchanging or rotating the spraying in different areas in next terms.Since 1985, this strategy has been adopted to control the aphids on vegetables in Meilong, a suburban county of Shanghai. The aphids included Lip-phis erysimi pseu dobrassicae, Myzus persicae and Cavariella salicicoia. Based on bioassay and determination of a-Na esterase activity in single aphids, we found mosaic rotation of dimethoate and fenvalerate can delay the development of insecticide resistance in the above three species of aphids, as compared with continued use of dimethoate followed by continued use of fenvalerate to the point where control was impaired by resista nce.

Key words: aphid——insecticide resistance——mosaic rotation control