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我们县地处吉林省的中南部,是一个六山一水三分田的半山区。随着林业生产的飞速发展,由于过去种苗引调频繁,检疫工作不严,致使森林病虫害日趋严重。特别是松毛虫的危害尤为猖獗,轻者影响林木的正常生长,重者造成林木大片频死,直接威胁着落叶松和黑松人工林的发展。在省林业科学研究所的帮助指导下,我县从1973年开展了以生物防治为主的综合防治,先后应用赤眼蜂、平腹小蜂、白僵菌、松毛虫杆菌等防治松毛虫,全县每年平均生物防治松毛虫面积,占松毛虫总发生面积的96.3%。几年来,由于坚持了生物防治,有效的保护了松毛虫的天敌,使松毛虫发生面积由1972年占松林总面积的36.9%,现在缩减到7.4%;有虫株率由原来的70%,降低到25%;虫口密度由原来的平均每株45头,下降到0.5
Our county is located in the central and southern part of Jilin Province, is a Mid-Levels mountain area of six hills and one water. With the rapid development of forestry production, due to the frequent introduction of seedlings in the past and the lack of strict quarantine work, forest pests and diseases have become increasingly serious. Particularly, the damage of pine caterpillars is especially rampant. The light ones affect the normal growth of trees. The severe ones cause the frequent death of forest trees, which directly threatens the development of larch and Pinus thunbergii plantation. Under the guidance of the help of the Provincial Forestry Science Research Institute, our county started the comprehensive prevention and treatment with biological control mainly in 1973, and has successively applied Trichogramma, Trichogramma, Beauveria bassiana, The average annual area of biological control of pine caterpillars, accounting for 96.3% of the total area of pine caterpillars. In recent years, due to adherence to biological control, effectively protect the natural enemies of pine caterpillars, so that the occurrence area of pine caterpillars accounted for 36.9% of the total area of pine forests in 1972, now reduced to 7.4%; worm strains from the original 70% Reduced to 25%; population density from the original average of 45 plants per head, down to 0.5