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1992年,棉铃虫在华北、东北广大棉区特大暴发,第一代在小麦上猖獗发生,使部分麦田小麦严重受害,随后第2～4代在棉田和其它作物上特大暴发成灾,发生数量为常年的15—20倍,发生危害面积达5000多万亩,占全国棉田面积一半以上。1 1992年棉铃虫猖撅发生概况在黄河流域棉区棉铃虫常年以2代在棉田发生量大,仅少数年份3代或4代发生猖獗,有历史记载的棉铃虫大发生年份,也是个别世代大发生,造成局部棉田减产。1992年则是全年棉铃虫的4个世代均特大发生,一
In 1992, the cotton bollworm broke out in the vast cotton areas of North China and Northeast China. The first generation was rampant in wheat, causing serious damage to wheat in some wheat fields. The second to fourth generations of large-scale outbreaks in the cotton fields and other crops subsequently took place, 15-20 times as many perennials, with the harms of more than 50 million mu, accounting for more than half of the national cotton area. In 1992, cotton bollworm occurred in the cotton area in the Yellow River valley perennial generations occurred in the second generation of large, only a few years of third or fourth generation rampant, there are historical records of bollworm occurrence of large, but also individual generations Big occurred, resulting in reduced production of local cotton. In 1992, the four generations of cotton bollworms all took place exceptionally