菜蛾(Plutella Xylostella L.)(异名Plutella maculipennis Curtis)是内蒙古地区为害十字花科蔬菜的主要害虫之一,为害率一般在30～90％,对蔬菜的产量和品质影响很大。由于菜蛾在我区的生活史至今尚未完全清楚,不能很好掌握关键时期及时用药防治,因此防治效果低,同时大量施用化学农药,使害虫产生抗性,杀伤天敌、污染环境,影响人民身体健康。我们结合学生实习,从1986～1989年在本院通过室内饲养和田间观察,对菜蛾的生物学特性进行了初步研究。 (一) 生活史菜蛾在呼和浩特市地区一年发生6～7代,约经15～30天完成一个世代。越冬代成 Plutella xylostella L. (synonym Plutella maculipennis Curtis) is one of the major pests of cruciferous vegetables in Inner Mongolia. The damage rate is generally 30-90%, which has a great impact on the yield and quality of vegetables. As the life history of Plutella xylostella in our district has not yet been fully understood, it is not possible to control the timely application of drugs in key periods so that the effect of prevention and treatment is low. At the same time, chemical pesticides are used in large quantities to cause resistance to pests, injure natural enemies, pollute the environment and affect people’s health health. We combine the student internship, from 1986 to 1989 in our hospital through indoor feeding and field observation, the biological characteristics of the diamondback moth conducted a preliminary study. (A) life history of moth in Hohhot area occurs 6 to 7 generations a year, about 15 to 30 days to complete a generation. Overwintering generation into