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松毛虫是严重威胁落叶松林的森林害虫,食量大、繁殖力强,高温干旱年分则大量发生,并造成严重灾害。1980～1982年阿尔山和乌尔旗汉地区松毛虫大量发生,使大片落叶松林受到严重危害。乌尔旗汉林业局,78年以前没发生过松毛虫,79年在人工林内少量发现,80年个别地段被害率达26％。81年由于气候条件适宜,人工林内松毛虫大量发生,受害面积达5万多亩,其中危害严重的有4千多亩,被害率100％,虫口密度60个/株,最多达781个/株。被害林分仅一个月时间,树叶即被全部吃
Dendrolimus is a forest pest that seriously threatens the forest of larch. The food intake is large, the fertility is strong, and the high temperature and drought years occur in large numbers and cause serious disasters. From 1980 to 1982, a large number of pine caterpillars occurred in the Aershan and Urqi areas, causing large-scale larch forests to be severely endangered. Wuerqi-Han Forestry Bureau, 78 years ago, there have been no loose caterpillars, 79 years found in small quantities within the plantation, 80 were killed in individual sections of 26%. Due to the suitable climatic conditions in 1981, a large number of pine caterpillars occurred in the plantations, covering an area of more than 50,000 mu, of which 4,000 mu were seriously endangered, 100% were killed, and the density of pests was 60 per plant up to 781 plants per plant . Only a month’s time, the leaves were all eaten