菜青虫国内分布普遍，各省均有发生，尤以北方发生最重，是北方十字花蔬菜上的重要害虫。该虫主要为害甘蓝、花椰菜、白菜、萝卜、油菜十字花科蔬菜，偏嗜厚叶类蔬菜。 一、为害特点 幼虫咬食寄主叶片， 2龄前仅啃食叶肉，留下一层透明表皮， 3龄后蚕食叶片孔洞或缺刻，严重 Cabbage caterpillars widespread in the country, all provinces have occurred, especially in northern heaviest occurrence, is an important pest on the northern cross-flowered vegetables. The insects mainly cabbage kale, cauliflower, cabbage, radish, Brassicaceae cruciferous vegetables, partial preference thick leafy vegetables. First, the harmful characteristics of larvae bite the host leaves, only two eating grass before the 2nd leaf, leaving a layer of transparent epidermis, 3 years after eating the leaves holes or nicks, serious