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花县毗邻广州市北部郊区,北接粤北山区,南连珠江三角洲北缘,是一个以丘陵为主的地区。1958年以前,由于水利问题未彻底解决,耕作制度以双季稻为主,单双并存,加上虫害严重,稻谷产量一直不能稳步上升。1958年以后,由于“流溪河”灌溉工程建成,双季连作稻的耕作制度稳定下来,同时大力推广以化学农药为主的防治害虫措施,收到显著效果。如三化螟的为害,从1956、1957年早稻白穗率分别高达25％和12.7％,被控制到常年不到1％。但1971年以后,稻、稻、麦一年三熟制逐步推广,加上近几年来冬春期干旱,和长期大量使用化学农药带来的某些副作用,不但三化螟的为害有较明显的上升(如1971
Huaxian adjacent to the northern suburbs of Guangzhou City, north of northern mountainous areas in the north, north of the Pearl River Delta, is a mainly hilly areas. Before 1958, due to the incomplete solution of water conservancy issues, the double-cropping system in the farming system was dominated by single-cropping and pests were severe. The output of paddy crop could not be steadily increased. After 1958, thanks to the completion of the “Liuxi River” irrigation project, the farming system of double cropping and continuous cropping rice stabilized. At the same time, efforts were made to promote pest control measures mainly based on chemical pesticides and received remarkable results. Such as the yellow rice borer damage, from 1956, 1957 early rice white spike rates were as high as 25% and 12.7%, was controlled to less than 1% of the perennial. However, after 1971, rice, rice and wheat are gradually popularized in three crops a year. In addition, due to the drought in winter and spring in recent years and some side effects caused by the long-term use of chemical pesticides, not only the damage of the rice stem borer is more obvious (Such as 1971)