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由于棉铃虫对多数农药产生抗性以及生态条件改变等多种原因,很多棉株主茎顶心被虫子吃掉,成为无头棉。近几年,有了抗虫棉,棉铃虫对棉花的危害受到了抑制。但是棉花苗期由于对棉蓟马、小地老虎等害虫忽视适期防治,又使很多棉株顶心被害,而成为无头棉。据调查,受害轻的棉田,主茎顶心受害株率为20%～40%;受害重的棉田,受害株率高达60%～70%。由于棉株主
Due to the cotton bollworm resistance to most pesticides and ecological conditions change and many other reasons, many of the main stem of cotton stem eaten by insects, as a cotton-free. In recent years, with insect-resistant cotton, cotton bollworm damage to cotton has been suppressed. However, due to the cotton seedling stage thrips, small tiger and other pests neglected the proper control, but also to a lot of cotton plants were killed, and become a headless cotton. According to the survey, the light damage of cotton fields, the top of the main stem damage rate of 20% to 40%; victims of heavy cotton fields, victims of strain as high as 60% to 70%. Because of the cotton plant owner