杨树细菌溃疡病损失估计的研究

Studies On Loss Assessment of Poplar Bacterial Canker

在杨树细菌溃疡病严重发生的吉林省抚余市，分别不同林龄和立地条件，选设具有代表性的样地。对高度感病的树种美×青，（PopuluspyramidalisxP．cathayana），采用野外均匀分布，典型整群抽样调查和树干解析的方法，获得20块样地60株解析本的调查数据，确定了病情指数与材积损失率的相关数率。建立了杨树细菌溃疡病材积损失估测的最佳模型，为Richards方程L＝54．8800（1－e-0．0296d）1．6959，并以此推算出相应的经济危害允许水平和防治指标的计算模型。

in the areas where the Poplar bacterial canker seriously broke out, the representative plots of susceptible Populus Pyramidalis x P. cathayana were chosen and established according to differert ages and sites. The correlation formula between volume losses rate anddisease index was determined by the method of uniform distribution, typical population sampling and stem analysis in the field. The results of regression on analysis on different typesof curves with the data of 60 trees of stem analysis and 20 samp plots shawad that Richardsequation L = 54. 8800 (1-e-0. 0296d )1. 6959 was screened as the superior loss assessment model.The corresponding models of Economic injury Level and Economic Threshold were also calculated.