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近两年来,我县三化螟的回升势头大增,尤其是1990年,回升更猛。据调查:1988年每亩三化螟幼虫越冬基数只有100～200头;1989年400～500头,1990年猛增到1200～1500头,1991年达2100～3500头。由于这一害虫的回升,给水稻生产造成了一定的损失。据不完全统计,1988年水稻因受三化螟为害损失的稻谷约4万公斤,1989年达20万公斤,1990年猛增到47.5万公斤,其中以第四代为害最重.1990年9月10日,我们在本县聂桥乡调查,每亩有卵块一般在30～40块,高的60～70块,9月24日在米粮铺乡前山村调查,防治较好的田块自穗
In the past two years, the rebound momentum of the rice stem borer in our county has been greatly increased, especially in 1990, with a fiercer recovery. According to the survey, in 1988, the number of overwintering basal larvae on the stem borer was only 100-200; in 1989, it was 400-500 heads. In 1990, the larvae jumped to 1,200-1,500 heads in 1991 and 2100-3,500 heads in 1991. As a result of the pest’s recovery, it has caused some losses to rice production. According to incomplete statistics, about 40,000 kilograms of paddy rice was damaged by the rice stem borer in 1988, reaching 200,000 kilograms in 1989 and 475,000 kilograms in 1990, of which the fourth generation was the hardest hit. On the 10th of this month, we surveyed Nieqiao Township in our county. There are 30-40 eggs per acre and 60-70 high. On the 24th September, Since the ear