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长管蚜是京郊麦田的重要害虫。常在抽穗后大量繁殖危害造成千粒重下降。在蚜害损失年,小麦的减产程度与蚜量激增始期出现的早晚有关。据测定抽穗扬花期蚜量开始激增可减产14%,扬花后五天蚜量开始激增可减产8%。小麦上蚜量的增加表现为有蚜株及单株蚜量的增加,一般抽穗前以有蚜株增加为主;抽穗后一定时期以单株蚜量增加为主;二者的交接点是有蚜株率50%,百株蚜量300头左右,定为蚜量激增始期。麦田有翅蚜有4次迁飞高峰;第2次迁飞高峰以后即出现蚜量激增始期。根据翅蚜突增
Aphis gossypii is an important pest in the wheat fields in Beijing. Often after a large number of heading threatened to cause weight loss. In the year of loss of aphids, the yield reduction of wheat is related to the early or late onset of aphid-induced stress. According to the determination of flowering population of aphids at the beginning of the surge can be reduced by 14%, five days after flowering aphids began to surge can be reduced by 8%. The increase of the amount of aphids on wheat showed the increase of the amount of aphid and single aphid. Before the heading, the number of aphid increased, while that of aphids per plant increased after a certain period of heading. Aphid plant rate of 50%, about 100 aphids amount of 300 or so, as aphids stimulus period. Aphis gossypii has 4 times the peak of relocation in the wheat field; after the second peak of migratory appears aphid stimulating onset. According to the sudden increase of winged aphids