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三化螟在我县一年发生四代。影响其发生数量的主要因子是气侯条件,其次是耕作制度,我县耕作制度自1963年以来,虽然有所变化,但单季中稻面积历年均在五万亩左右,占水稻总面积的五分之一,为单双混栽区。由于耕作制度变化不大,因此我县螟虫在发生数量年度之间的差异,主要是受气侯条件影响所致。但自晚稻推广杂交水稻后,由于杂交水稻营养丰富,我县第四代三化螟危害有加重趋势。运用数理统计方法分析环境条件引起螟虫的数量变动,进行数值预报,将是测报手段逐步走向模式化,电子化的基础,现将我县1963—1978年三化螟一至四代灯下发生量数值预报整理如下。
Three generations of rice borer occurred in our county four generations a year. The main factors influencing the occurrence are the climatic conditions, followed by the tillage system. Although the tillage system in our county has changed since 1963, the area of single-season middle rice is about 50,000 mu each year, accounting for five of the total rice area One for the single mixed planting area. Due to the little change in farming system, the difference between the annual occurrence of stem borers in our county is mainly due to the impact of climate conditions. However, since the late rice to promote hybrid rice, rice hybrids due to nutrient-rich, the fourth generation of rice borer in our county there is a growing trend of harm. The use of mathematical statistics to analyze environmental conditions caused by changes in the number of borers, numerical prediction, will be the means of measurement and reporting toward the pattern of electronic, based on the counties in our county 1963-1978 generation of light one to four generations under the lamp Forecast is organized as follows.