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经过对纵坑切梢小蠹 (TomicuspiniperdaL .)种群密度和云南松 (PinusyunnanensisFranch .)生长状况的长期、仔细的调查 ,加上改进的回归分析方法 ,得出了为害云南松的纵坑切梢小蠹防治上的经济阈值 :当林木枯死率不超过 0 .5 2 %时 ,自然控制因子能控制纵坑切梢小蠹种群不向高密度方向发展 ,因而可以不必防治。当林木枯死率达到 0 .5 0 % ,对应的枯捎率为 0 .6 1 % ,以及对应的平均每株侵入孔数为 0 .6 6时 ,防治费用和挽回损失价值相当。所以 ,若既考虑到经济上的合理性 ,又考虑到控制其种群不向高密度方向发展 ,当林木枯死率超过 0 .5 % ,对应的枯梢率超过 0 .6 1 % ,以及对应的平均每株侵入孔数超过 0 .6 6时 ,就有了进行防治的必要。本文还给出了各云南松林区可以用来根据自己的具体情况计算出适合自己的经济阈值的公式。
After long-term and careful investigation of the population density of Tomicus piniperda L. and the growth of Pinus yunnanensis Franch. Together with the improved regression analysis method, Economic Limits on Beetle Control: When the tree mortality does not exceed 0.52%, the natural control factor can control the growth of the Dendroctonus villosus population to a high density without the need for control. When the mortality rate of wood was 0.55%, the corresponding dry-cutting rate was 0.61%, and the corresponding average number of invasive holes per plant was 0.666, the control cost was equivalent to the value of recovery loss. Therefore, considering both economic rationality and the fact that the control of its population does not develop in a high-density direction, when the wood lethality exceeds 0.5%, the corresponding shoot rate exceeds 0.661% and the corresponding The average number of invaded holes per plant exceeds 0.6 6, there is a need for prevention and treatment. The paper also gives the formula that each pine forest in Yunnan can be used to calculate its own economic threshold according to its own specific conditions.