一九七六年五月中下旬棉苗2—3片真叶阶段,由于蚜虫猖獗,普遍卷叶,但在永济县任阳、于乡、清华等公社沿中条山一带的一些棉田,叶片舒展,长势茁壮。原因可能与当时棉苗上发生的微型外寄生螨(以下简称寄生螨)有关。为了验证此种螨类是否蚜虫的天敌资源,六月份在上述有关地方进行了田间调查和系统观察,初步证明棉蚜是寄生螨的食源,寄生螨是棉蚜的外寄生天敌。一、田间调查棉蚜发生的多少,危害的轻重,受到多种因素的影响和支配。为了观察寄生螨对蚜虫的真正控制作用,我们进行了以下调查研究。(一)茬口与棉蚜和寄生螨发生的关系 Mid-and-late May, 1976 Mid-and-late Mian Miao 2-3 true leaves stage, due to rampant aphids, the general roll leaves, but in Yongji County Ren Yang, Yu Township, Tsinghua and other communes along the strip of some cotton fields, Leaves stretch, growing robust. The reason may be related to the occurrence of micro-parasitic mites on cotton seedlings (hereinafter referred to as parasitic mites). In order to verify whether this mite is a natural enemies resource of aphids, a field survey and systematic observation were conducted in the above-mentioned places in June. It was initially proved that cotton aphid was the food source of parasitic mites, which are natural parasites of cotton aphids. First, the field survey cotton aphid how much, the severity of harm, affected by many factors and domination. In order to observe the true control effect of parasitic mites on aphids, we conducted the following investigation. (A) stubble and cotton aphid and parasitic mite occurrence