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掌握越冬螟虫虫口密度的变动规律,是进行第一、二代预测的重要依据。因此,越冬调查方法完善与否,对预测的准确程度密切相关。全国螟虫测报办法规定,越冬后的死亡率用调查时所获活虫数和死虫数来计算。这种方法在具体应用上,嫌有不足之处,即只能表示调查前15—20天的死亡情况,至于春前的死亡率。因虫尸业已腐烂无法查出。春前死亡情况,虽可通过多次调查获悉,但整个越冬期间的死亡率还是无法推算。笔者几年来一直采用“定点调查法”进行调查,以弥补一般调查方法的不足,使资料更加准确。现将
Grasp the variation of density of borer borer insect population, is an important basis for the first and second generation forecast. Therefore, whether the method of overwintering investigation is perfect or not is closely related to the accuracy of prediction. The national measure for the detection of stem borers provides that mortality after overwintering is calculated from the number of live insects and the number of dead insects collected during the survey. This method in the specific application, there are some shortcomings, that can only indicate the death of 15-20 days before the survey, as for the mortality rate before spring. Can not be detected because of dead rot corpse. Although the death before spring may be learned through multiple surveys, the mortality rate during the entire winter is still unpredictable. The author has been using the “fixed-point survey” for several years to investigate to make up for the lack of general survey methods to make the data more accurate. Now