长期以来，二化螟是我县水稻上的主要害虫，１９９０～１９９６年发生程度都达中等以上。近年来，由于水稻品种布局和育秧技术发生重大变化，二化螟生存环境和食料条件恶化，种群密度下降，危害减轻，为６０年代以来发生最轻的时期。本文对近两年二化螟发生轻的原因进行了探讨 For a long time, Sesamia inferens is the main pest on paddy rice in our county, and the degree of occurrence was above middle level from 1990 to 1996. In recent years, due to the significant changes in the rice variety layout and seedling raising technology, the living environment and feedstuff conditions of the rice stem borer have deteriorated. The population density has decreased and the harm has been alleviated. This is the lightest period since the 1960s. In this paper, the light of the occurrence of Chilo suppressalis in the past two years were discussed