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棉花是虫灾发生较为频繁的农作物之一。在整个生长期,用药次数之多、用药量之大,当数作物之首。近几年,由于采用药剂防治缺乏科学合理的施药方法,不仅造成人力、物力浪费,增加生产成本,还会使害虫产生抗性、增大除虫难度,污染环境。 除治害虫的目的并不是也未必能“赶尽杀绝”,而是将害虫数量控制在经济允许的受害水平之下。保留一定数量的害虫不仅有利于天敌种群壮大,抑制害虫繁衍为害,有时还能起到保持生态平衡,遏制棉田幼苗徒长等作用。因此棉田除虫时保护好天敌,是提高棉田综合防效的主要措施。
Cotton is one of the more frequent pest crops. Throughout the growth period, the number of medication, the amount of medication, when the number of crops first. In recent years, due to the lack of scientific and reasonable pesticide application methods, not only waste manpower and material resources, increase production costs, but also make pests resistant and increase the difficulty of insect pests and pollute the environment. Except for the purpose of controlling pests, they may not be “rushed to kill” but control the number of pests below the allowable level of economic injury. Retaining a certain amount of pests not only helps the population of natural enemies to grow stronger, restrain the multiplication of pests, but also can sometimes maintain the ecological balance and prevent the growth of seedlings in cotton fields. Therefore, the protection of natural enemies when the insect repellent cotton is to improve the comprehensive control of cotton fields the main measures.