Before and after the beginning of autumn each year, pests on cabbage are the key points and difficulties in prevention and control. Recently, some farmers have reported that their vegetables have been damaged, leaving only a transparent skin! They have taken the pesticides five or six times and used a considerable amount, but they just can't cure the bugs on the vegetables.They have no idea on what to do.

  经过一番沟通了解确认，确定为菜青虫危害。

  菜青虫主要为害甘蓝、白菜、花椰菜、油菜等十字花科蔬菜，以幼虫期咬食寄主叶片，2龄前仅咬食叶肉，留下一层透明表皮。3龄后蚕食叶片成孔洞或缺刻，4—5龄为暴食期，占整个幼虫期取食量的97%，只残留叶脉和叶柄，造成绝产。同时排出的粪便还污染菜心，使蔬菜品质变坏，引起白菜软腐病的流行，降低蔬菜的产量和品质。

  菜青虫，虫口量随季节变化很大，一般从4月中下旬到10月上旬均可发生，但以5~6月和8~10月发生为害重，所以要抓住秋季前后防治。

  由于菜青虫世代重叠现象严重，3 龄以后的幼虫食量加大、耐药性增强。因此，施药应在幼虫 1-2 龄盛期，使用九净^®、钉丝^®进行防治。