棉蚜为害一直是北方棉区的重要问题。在生产上存在着有蚜就有害、有蚜就治和定期打药的习惯。常造成农药和人力的浪费,又增加了生产成本,杀死天敌,影响生态平衡,引起次要害虫大发生,蚜虫产生抗药性,污染环境,人畜中毒等不良后果。因此,在摸清棉蚜为害规律的基础上,采用经济为害阈限,制定合理的防治指标,这不仅是害虫防治的总趋势,也是当前生产上急待解决的问题。研究方法一、研究是从1981年开始采用定株,定蚜量(为害10天)小区对比方法。1983年采用累积蚜害量的方法。选在土质肥沃、亩施万斤农家肥的一类田和土质瘠薄、水肥条件差的三类田各一亩。棉花密度为每亩6000和8000株。品种为76—78、辽棉八号(2105)和黑山棉一号。当棉花两片真叶和蕾期7片真叶时,各选生长一致的壮苗400株,每株接3～4龄若蚜两 Cotton aphid damage has been an important issue in the northern cotton area. In the production there is aphids on the harmful, there is aphid rule and regular fight drug habit. Often result in the waste of pesticides and manpower, but also increase the cost of production, kill natural enemies, affect the ecological balance, causing major pests, aphids produce drug resistance, pollute the environment, human and animal poisoning and other adverse consequences. Therefore, on the basis of finding out the damage rules of cotton aphid, adopting the threshold of economic harm and formulating the reasonable prevention and control index are not only the general trend of pest control, but also the urgent problems to be solved in current production. Research methods First, the study is from the beginning of 1981 Strain, the amount of aphids (damage 10 days) plot contrast method. In 1983 the cumulative amount of aphid damage method. Selected in the fertile soil, Mushi Shi Wan farmyard a class of farmland and soil infertility, poor water and fertilizer conditions of three kinds of fields each acre. Cotton density is 6000 and 8000 plants per acre. Varieties for the 76-78, Liaoning cotton eight (2105) and Montenegro cotton one. When the two true leaves and buds of cotton seven true leaves, the growth of the same election of 400 strong seedlings, each plant 3 to 4 years old, if aphids two