杉木幼林黄化,主要表现在枝叶变黄,生长衰弱,林相呈黄至红褐色。枯黄的程度随地形地势而异,无明显发病中心。枝叶上亦无病斑痕迹,经显微镜检查和组织分离均未发现病菌。几年后渐变为不生不死的“小老头”。鉴于杉木幼林黄化发生普遍,并严重地影响成林成材,为林业生产中急待研究解决的问题之一,1974年至1975年初,我们在广东省番禺县、东莞县和广州地区,作了初步观察,并结合开门办学,进行了一些分析和试验。 Young Chinese fir plantation, mainly in the branches and leaves turn yellow, weak growth, the forest phase was yellow to reddish brown. The degree of yellowing varies with the terrain, there is no obvious incidence center. Branches and leaves no trace of disease, microscopic examination and tissue separation were not found in bacteria. A few years later gradual change into a “small old man.” In view of the widespread occurrence of young plantations of Cunninghamia lanceolata and the serious impact on the success of the forestation, it is one of the problems to be urgently studied and solved in the field of forestry production. From 1974 to early 1975, we conducted the research in Panyu, Dongguan and Guangzhou in Guangdong Province Preliminary observations, combined with open-door school, conducted some analysis and experiments.