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黄刺蛾、青刺蛾的幼虫又叫“洋辣子”,是食性较杂、食量较大、分布较广的食叶害虫。除因食叶而影响林木、果树生长外,还与桑蚕、柞蚕争食。在我场的杨树人工林中,历年来为害严重,面积达两万亩以上,虽然每年要进行化防五千至一万亩,但因暴食期短,防治季节性强,在猖獗为害时,始终未得到控制。两年来,我们开展了利用防治松毛虫的赤眼蜂防治黄、青刺蛾的生防试验,初步获得了防治效果,同时也控制了柳天蛾、双尾舟蛾、杨枯叶蛾等十余种害虫的发生。黄、青刺蛾的卵是赤眼蜂的优良寄主卵之一,有着寄生率高的显著特点。我们在生产的实践中感到,只要适时适量进行放蜂,防治效果均可达90%以上。在今年一万五千亩的大面积放蜂区中平均寄生率为91.8%,最高寄生率达98.7%。据幼虫为害期调查,单株有茧由七六年的20头左右下降到0.2—0.5头,从两年的虫口密度对比可下降90%以上,取得了历年来进行化防所不及的防治效果(参看表1)。
Yellow thorn moth, green thorn moth larvae, also known as “spicy child” is a more food-eating, food intake, the wider distribution of leaf-eating pests. In addition to affecting the trees due to leaf, fruit trees grow, but also with silkworms, tussah fight food. In my field of poplar plantations, serious damage over the years, covering an area of 20,000 mu or more, although the annual anti-5,000 to 10,000 mu, but due to a short period of gluttony, prevention and control seasonal strong, when the rampant damage , Has not been controlled. In the past two years, we conducted a pilot study on the prevention and control of Trichogramma dendrolimi against Trichogramma dendrolimi and its preliminary prevention and control effects, as well as ten More species of pests. Yellow, green thorn moth eggs are Trichogramma excellent host eggs, has a significant feature of high parasitism. We feel in the practice of production, as long as the appropriate amount of time to put the bees, the control effect of up to 90%. The average parasitic rate in this large area of 15,000 hectares was 91.8% and the highest parasitic rate was 98.7%. According to the survey of larvae damage period, the cocoons per plant dropped from about 20 heads in 1976 to 0.2-0.5 heads, and the density of insects in two years could be reduced by more than 90% (See Table 1).