论文部分内容阅读
油桐(Aleurites fordii Hemsl.)是陕西省紫阳县重要的经济林树种之一,但在该县发现油桐感染带化病严重,病害呈点片状发生,根据在洞河、城关等地区调查,一般发病率为3％,严重的达7％,发病的油桐树龄为2—5年,以3年生幼树发病较严重。油桐带化病病变形态与香椿带化病病变十分相似。感病的油桐树在未发生病变的前一年,树高有生长迅速的特点,一般在病枝以下的一节(于两侧枝之间)一年内高生长达3—4m。病树最显著的病状是新生的枝条呈扁平的带状,尖端卷曲或扭曲生长,如同一把大刀,有的形成齐头铲状,最宽处可达13cm,病枝叶片明显变小(图5);当枝梢孕育花芽亦能开花座果,果实仅有正常成熟果实大小的1/4,萎缩枯死,影响油桐树的正常生长及桐油产量。此病的蔓延阻碍了油桐树的发展。
Aleurites fordii Hemsl. Is one of the most important economic tree species in Ziyang County, Shaanxi Province. However, in the county, the infection of Tung Oil trees was found to be serious and the disease appeared flaky. According to the investigation in Donghe and Chengguan areas, The general incidence of 3%, severe up to 7%, the incidence of tung oil tree age of 2 - 5 years, with 3-year-old saplings more serious. Cordyceps diseased lesions with Toon disease with pathogenic is very similar. Sick tung tree in the absence of lesions the year before, the tree has a rapid growth characteristics, usually in the next branch of the disease (between the two branches) within a year of high growth up to 3-4m. The most prominent symptoms of diseased trees are newborn branches were flat ribbons, tip curly or twisted growth, like a sword, and some form scoop-shaped, the widest point up to 13cm, sick leaves significantly smaller (Figure 5). When the shoots were also flower buds blooming fruit, fruits only the size of normal mature fruit 1/4, shrinkage dead, affecting the normal growth of tung tree and tung oil production. The spread of the disease hindered the development of tung tree.