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我国北方九省(区)松毛虫主要有赤松毛虫、油松毛虫和落叶松毛虫三种。赤松毛虫常见于山东、辽宁两省及河北东部林区,油松毛虫多发生在河北、山西、陕西三省,落叶松毛虫分布在东北三省到新疆一带。仅据山东、辽宁、吉林、河北四省一九七二年统计,松毛虫发生面积800余万亩,约占松林总面积的30％左右。有些林区,由于松毛
China’s northern nine provinces (regions) mainly Dendrolimus Dendrolimus, Dendrolimus tabulaeformis and Dendrolimus caterpillar three. Dendrolimus cochlear is common in Shandong, Liaoning provinces and the eastern part of Hebei, Dendrolimus tabulaeformis occurred in Hebei, Shanxi and Shaanxi provinces, and the larch caterpillars distributed in the three northeastern provinces to Xinjiang. According to statistics of 1972 in Shandong, Liaoning, Jilin and Hebei provinces, the area of pine caterpillars exceeded 800 million mu, accounting for about 30% of the total area of pine forests. Some forest areas, due to loose hair