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对北欧经济起重要作用的森林,近十年来遭到害虫的严重为害,1969年秋,一场大风使大片森林风倒,由于面积较大,不能及时清理,这些倒木遭到小蠹虫的严重为害。开始用DDT等杀虫剂进行防治,1975年瑞典政府禁止使用DDT后改用六六六,但这种药剂除杀死小蠹虫外,还能杀死其它昆虫。对小蠹虫的传统防治方法是在冬末伐倒老树留在林中,待气温上升到18℃时,小蠹虫就会爬上倒木,然后将倒木及时运出消毁,用这种方法杀死小蠹虫成
Forests that played an important role in the Nordic economy were severely damaged by pests in the past decade. In the autumn of 1969, a large wind sent large forest winds and, due to the large area, could not be cleared in time, they were severely damaged by beetles. Began to use DDT and other pesticides to prevent and control, in 1975 the Swedish government banned the use of DDT after the switch to six six six, but this agent in addition to kill beetles, but also kill other insects. The traditional method of controlling bark beetle is to remove the old tree in the forest at the end of the winter. When the temperature rises to 18 ° C, the bark beetles will climb down the fallen wood and the fallen tree will be transported out to be destroyed in time. In this way Dead beetles into