Bt抗虫棉棉田棉铃虫防治指标研究

A Study on the Control Index of Cotton Bollworm in Transgenic Bt Cotton Fields

经 1996～ 1999年 4年试验观察 ,Bt抗虫棉棉田棉铃虫卵至三龄幼虫存活率 ,二代为 1.3% ,三代为 5.5%。田间幼虫与被害蕾铃比分别比普通棉田提高 35.1%和 2 1.3%。结合对普通棉田复合防治指标研究 ,初步确定Bt抗虫棉棉田棉铃虫防治指标为 :二代百株幼虫 5.2头或百株卵量 4 0 0粒 ,三代百株幼虫 4 .7头或百株卵量

In an experiment of 4 years from 1996～1999,it was observed that the survival rate of cotton bollworm eggs to the second generation of 3-instarlarvas was 1.3%,the third generation was 5.5% in transgenic Bt cotton fields.The ratio of larvas to damaged bolls in transgenic Bt cotton fields was increased by 35.1% and 21.3%,compared to that observed in common cotton fields.Combined with the complex control index of common cotton fields,it was preliminarily considered that the control index for transgenic cotton was the second generation larvas 5.2 or 400 eggs/100 plants,the third generation larvas 4.7 or 85 eggs/100 plants.