棉铃虫是山东省棉花的主要害虫,1992年在全省特大暴发,发生范围之广,卵量之高,为害之重,是历史罕见的,现就大发生的原因初步剖析如下:1 山东棉铃虫发生演变情况五十年代,棉铃虫不是棉花的主要害虫,1965年前,只有四次发生较重。以后逐步上升为棉花的常发性害虫,七十年代成为棉花的重要害虫,发生程度越来越重,八十年代重于七十年代,九十年代重于八十年代。1992年特大暴发,为历史上最重的一年。以二代为例,德州、聊城等6个主产棉地市,百株累计卵量七十年代平均197.2粒,八十年代平均341.6粒,卵量增加73.23%。1991年 Cotton bollworm is the major pest of cotton in Shandong Province. In 1992, the outbreak of the disease was widespread in the province. The occurrence of the bollworm was widespread and the number of eggs was extremely heavy. It was a rare occurrence in history. The reasons for the occurrence of the bollworm are as follows: In the 1950s, cotton bollworm was not the major pest of cotton. Before 1965, there were only four serious occurrences. After the gradual rise to cotton pests, the seventies become an important pest of cotton, more and more serious, eighty years in the seventies, ninety years in the eighties. The 1992 grand outbreak was the heaviest year in history. Taking the second generation as an example, six major cotton producing cities, including Texas and Liaocheng, produced an average of 197.2 eggs in the 1970s and an average of 341.6 eggs in the 1980s. The number of eggs increased by 73.23%. year 1991