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一、问题的提出三代棉铃虫是莱西县夏玉米穗期的常发性主要害虫,尤其是进入80年代以来,发生程度多在中等(3级)以上,一般使玉米减产5—7%,重时达10%以上。莱西县夏玉米面积,历年都在30万亩左右,因此搞好三代棉铃虫的测报工作,具有重要意义。本文运用转移矩阵的方法,根据一代棉铃虫的发生程度预测三代棉铃虫的发生程度。这样可变短期预报为中长期预报,大大提高防治工作的主动性。二、棉铃虫在莱西县的发生概况棉铃虫在莱西县一年发生4代。第一代发生在5月下旬到6月上旬,主要为害小
First, the issue put forward Three generations of cotton bollworm is Laixi summer maize spikes of the main pests, especially since entering the 80’s, the occurrence of more than moderate (level 3) above, the general reduction of corn 5-7% Heavy up to 10% or more. Lacey summer maize area, over the years are about 30 acres, so do a good job of three generations of cotton bollworm newspaper, is of great significance. In this paper, the transfer matrix method was used to predict the occurrence of three generations of cotton bollworm according to the occurrence of one generation of cotton bollworm. This variable short-term forecast for the long-term forecast, greatly enhance the prevention and control of the initiative. Second, the occurrence of cotton bollworm in Laixi County Cotton bollworm occurred in Laixi County four generations a year. The first generation occurred in late May to early June, the main damage to small