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近几年来,由于大面积营造人工油松纯林,加之综合治理差,致使丰宁县每年有近4万余亩林分被油松毛虫危害,成灾面积达2万余亩,有的林分5％的树木被其为害致死,给林业生产带来巨大损失,为了进行有效预测预报工作,以指导防治措施的落实,提高治虫的经济效益,1985年我们在丰宁县云雾山林场人工油松林内,对油松毛虫的携卵量进行了实际测算。采蛹的方法:分为受害轻的林分33％,中度受害林分33％,严重成灾林分33％。
In recent years, due to large areas of artificial pure pine plantation, combined with the poor comprehensive management, resulting in Fengning County each year nearly 4 million mu of trees harmed by oil pine caterpillars, disaster area of 20,000 acres, and some stands In order to carry out effective prediction and forecasting work, to guide the implementation of prevention and control measures and improve the economic benefits of pest control, 5% of the trees were killed by their harmful effects on forestry production. In 1985, we found that in the artificial pine forests of Yunwu Mountain Forest Farm in Fengning County , The amount of entomogenous Osteoporosis eggs carried the actual measurement. Pupae method: divided into victimized light forest 33%, moderately affected forest 33%, seriously damaged forest 33%.