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棉田害虫再猖獗的根本原因是由于生态系统平衡失调所造成的。棉田生态系统的特征有二:一是受农田生态所制约,主要受农作物布局所决定;二是由棉株为中心所构成。棉株不同发育阶段将提供不同的营养物质和化学信息;在不同的发育阶段棉田生态中,天敌和害虫种群消长规律在动态中保持相对的稳定和平衡。如果棉田生态中的食物链被破坏,必将引起天敌和害虫种群消长的比例失调,从而造成不同程度的经济损失。如果善于掌握和利用自然中天敌对害虫的控制作用,比如保护棉四天敌的中间寄主,把自然中天敌引入棉田活动繁殖,在害虫种群数量大发生前有庞大的天敌种群数量,足以控制害虫的发生量不造成棉花的经济损失,就能确保棉花的稳产、高产。
The root cause of the resurgence of pests in cotton fields is due to the imbalance of ecosystems. Cotton field ecosystem has two characteristics: one is subject to the constraints of farmland ecology, mainly determined by the layout of crops; the second is composed of cotton plants as the center. Different stages of cotton plants will provide different nutrients and chemical information; in different developmental stages, the population dynamics of natural enemies and pests maintain relatively stable and balanced in the dynamic. If the food chain in cotton ecosystem is destroyed, it will inevitably lead to imbalance of population growth and decline of natural enemies and pests, resulting in different degrees of economic losses. If we are good at grasping and using natural enemies of pests on the control role, such as the protection of the four hosts of cotton intermediates, natural enemies into the cotton field activity propagation, large pest population before the occurrence of a large population of natural enemies, enough to control pests The amount of cotton does not cause economic losses, we can ensure that the cotton yield, high yield.