Disease Law and Forecasting of the Needle Blight ofPinus sylvestris var. mongolica

Fixed quadrates were established in different stands. In continued six years, the occurring period, occurring amounts and the relation between epidemic disease and environmental factors were investigated according to spraying lawsof spores and accounting measures of disease ranking. The occuring peak period of the disease was from the last ten days ofMay to the second ten days of June. The epidemic period was from the last ten days of June to the second ten days of Julyand the initial decease period was from the last ten days of July to the beginning of September. The change of the diseasedepended on air temperature, relative humidity and precipitation. A multiple linear regression model was established usingcomputer, which can predict the disease index(Y) of 10 days later, with more than 95% reliability

Spatial distribution of needle bright disease of Pinus sylvestris var.mongolica

The spatial distribution pattern of needle bright disease was mathematically studied. The results showed that it is tally with negative binomial distribution. The infected area and damaged amount can be forecasted with this spatial distribution pattern. Through the study on probability distribution of spatial points for single tree, the method and equations for calculation of the disease index of whole forest belt were determined.

樟子松针枯病防治指标的研究

为制定合理的防治措施，对樟子松针枯病进行了木材损失及相应的损失模型和防治指标的研究。结果表明，经济危害允许水平为３１２０３，防治指标为：病情指数为３１以上时，叶面积损失每株达２４０４４３８ｍ２，影响较大，应进行防治；病情指数小于３１时。