橡胶树(Hevea brasiliensis)褐皮病的症状特点是割线上下皮层有明显的褐斑病灶,排胶减少或不排胶。病树树冠上还往往会发生枝条变扁、畸形、缩节、丛枝,顶部叶片变小成簇的丛枝病。有丛枝病的芽接树,90％会同时发生褐皮病,其余在1/2～1年也会发生褐皮病,两者关系密切。电镜检查,在无性系GT1及RRIM600病树树干韧皮部筛管细胞发现多形态类立克次氏体(RLO),菌体大小分别为100～2400nm和275～1395nm;在GT1根部的RLO为576～825nm;在IAN6645及PB28/59病树树冠上表现有丛枝病症状的病枝里为球形和椭圆形,大小为390～920nm;病树RLO壁厚约20nm。上述健康对照树均没有发现RLO。因而认为树冠的丛枝可能就是橡胶树褐皮病的一种症状。 七年(1979～1986)研究表明,橡胶褐皮病树经注射或环状刮皮涂保01、青霉素及四环素后,胶乳及干胶产量比对照树明显增产,病情减轻,其中以“保01”的效果最好,药剂有效持续期为3～6个月。药物处理对中、轻病树效果较好,对重病树效果较差。 根据上述试验结果,我们认为RLO是橡胶树褐皮病的病原。 Symptoms of Hevea brasiliensis brown-skin disease are characterized by significant brown spot lesions in the upper and lower cut lines, with reduced or no gel discharge. Tops of diseased trees also tend to occur branches become flat, deformity, contractions, Congzhi, the top of the leaves become smaller clusters of branches disease. There buds tree buds, 90% will be accompanied by brown skin disease, the remaining 1/2 to 1 years will also have brown skin disease, the two are closely related. Electron microscopy showed that RLO was found in the trunk cells of clonal phloem of GT1 and RRIM600 diseased clones, with cell sizes of 100 ~ 2400 nm and 275 ~ 1395 nm, respectively. The RLO of GT1 roots was 576 ~ 825nm. The lesions in the branches of IAN6645 and PB28 / 59 showed spherical and oval branches with the size of 390-920nm. The wall thickness of RLL was about 20nm. No RLO was found in the above healthy control trees. Therefore, that the crown of the branches may be a symptom of rubber tree brown disease. Seven years (1979 ~ 1986) studies have shown that the rubber brown skin disease tree by injection or annular scraping coat 01, penicillin and tetracycline, latex and dried gum production significantly increased compared with the control tree, the disease alleviated, which “Paul 01 ”The effect is best, effective duration of 3 to 6 months. Medication on the disease, mild disease tree better, less effective on severe disease tree. Based on the above test results, we consider that RLO is the causative agent of rubber tree brown disease.