Based on the mentioned results above, it is suggested that the populations of cotton bollworm in middle and northern parts around the Bohai sea immigrate from the south.

• 鉴于环渤海湾南部地区防治棉铃虫的化学农药使用量明显高于北部地区,二地棉铃虫抗药性水平年度间较为一致的结果表明，环渤海湾北部地区棉铃虫由南部地区迁入。