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一、棉铃虫的发生演变 50年代,棉铃虫还不是山东棉区的主要害虫。60年中期以前只有4次大发生;1965年后成为常发性害虫。70年代后则上升为棉花的重要害虫。进入80年代,又呈逐渐加重趋势。且不同代表现不同:二代上升,三代下降,四代上升。现分别介绍如下: 1.二代:据聊城、德州、菏泽、济宁、惠民和淮坊6个主产棉地市调查,二代百株累计卵量1979年前在76～317.2粒之间,平均197.2粒;1980年后在122.5～453.1粒之间,平均319.9粒。后12年比前10年平均卵量增加122.7粒,增加62.2％,其中聊城地区增加最多,
First, the evolution of cotton boll worm In the 1950s, cotton bollworm is not the main pest in Shandong cotton area. It occurred only four times before the mid-60’s and became a permanent pest after 1965. After the 70s rose to an important pest of cotton. Into the 80’s, but also gradually increase the trend. And the different representatives are different: the second generation rose, the third generation decreased, the fourth generation increased. Now introduced as follows: 1. The second generation: According to Liaocheng, Texas, Heze, Jining, Huimin and Huaifang 6 major cotton markets survey, the second generation of 100 cumulative eggs before 1979 in the range of 76 ~ 317.2 tablets , An average of 197.2 tablets; after 1980 between 122.5 ~ 453.1 tablets, an average of 319.9 tablets. After 12 years than the previous 10 years the average amount of eggs increased 122.7, an increase of 62.2%, of which Liaocheng increased most,