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桂阳县地处湘南,属南岭双季稻区。是迁飞性害虫主要为害区,也是稻飞虱发生为害的“特区”。近几年来,由于大力推广双季杂交水稻,稻飞虱出现了四个新情况。1.大发生频率增加。我县大面积种植杂交早稻是1985年,到1989年种植面积已占早稻面积的61.25%。就是在这短短的五年间,早稻稻飞虱已连续四年大发生。1971年至1984年的14年间,大发生或接近大发生的只有二年,大发生频率为14.28%。田间百丛虫量也明显高于历年平均值。以第二代若虫高峰(全国为三代)的田间虫量为例,五年平均为8054只,其中
Guiyang County is located in southern Hunan, Nanling double cropping rice. It is the main area affected by the migratory pests and also the “special zone” where planthoppers occur. In recent years, due to vigorously promote double crop hybrid rice, planthopper appeared four new situations. 1. The frequency of occurrence increases. The large area of early hybrid rice planted in our county was in 1985, and the planted area accounted for 61.25% of the area of early rice in 1989. It is in this short span of five years that early rice planthoppers have occurred for four consecutive years. During the 14 years between 1971 and 1984, the occurrence or occurrence of major or minor occurrences was only two years, with a frequency of 14.28%. The amount of hundred insects in the field was also significantly higher than the historical average. Taking the second generation nymphs peak (three generations of the country) field of insects as an example, the average of five years is 8054, of which