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通过对转 Bt基因抗虫棉田棉铃虫的系统调查研究表明 :(1)转 Bt基因抗虫棉对棉铃虫蛾、卵无抗性表现 ,田间落卵量与常规棉田无明显差异 ,相反 ,二代棉铃虫百株累计卵量倒比常规棉处理区增加了 2 16～ 2 74粒 ,增长幅度为 30 %～ 38% ;(2 )转 Bt基因抗虫棉对二代棉铃虫幼虫的抗性及控制作用较强 ,基本不用进行药剂防治 ,但对三代棉虫幼虫的抗性控制效果明显下降 ,田间 3龄以上幼虫平均达2 0～ 4 0头 /百株 ,多者达 6 0头以上 ,仍需进行必要的药剂防治 ;(3)棉铃虫在转 Bt基因抗虫棉株上的危害特点与常规棉株有明显的差异 ,表现在幼虫和危害症状均较隐蔽 ,不易被发现。
The results showed that: (1) The Bt transgenic cotton had no resistance to H. armigera and eggs, and there was no significant difference between the field and the conventional cotton field. On the contrary, The results showed that there was an increase of 2 16 ~ 2 74 seeds per 100 eggs in cotton bollworm, which was increased by 30% ~ 38% compared with the conventional cotton treatment area. (2) The resistance of transgenic Bt cotton to second-generation cotton bollworm larvae The control effect on the three generations of cotton larvae was obviously decreased. The number of larvae of 3rd instar and above in the field averaged 20 ~ 40 heads per 100 lines, with the number of more than 60 , Still need to carry out the necessary chemical control; (3) The characteristics of cotton bollworm on Bt transgenic cotton plants have obvious differences with the conventional cotton plants, showing larvae and harm symptoms are more hidden, not easy to be found.