【摘要】 泡桐丛枝病是影响泡桐生长的严重病害,此病在我国分布甚广,尤以华北平原为害严重。最常见病状为丛枝型,极少见花变枝叶型。健康泡桐实生苗经病树皮嫁接表现典型丛枝病状。用电镜观察病枝叶的超薄切片,在韧皮部筛管中发现有大量类菌原体(MLO)。类菌原体圆形或椭圆形,直径约为200—820nm,具有10nm厚的单位膜。用病枝叶汁液接种不能传病。病树的种子不带毒,采用种子育苗可减少丛枝病的发生。用病树根及带毒苗繁殖可以传病。防治丛枝病可推广种子繁殖。严禁从病区引种种根和苗木。用40—50℃温水浸种根30分钟或用1000单位四环素溶液浸种根12小时。用10000单位四环素、5%硼酸钠注入病树干基部髓心或用根吸方法,都有明显治疗效果。更多还原

【Abstract】 Witches broom on Paulownia is one of the most serious diseases inChina.In havily infected afforestation more than 80% of the cultivaedtrees were infected.Axillary buds proliferate and produce many se-condary and tertiary shoots which are covered with small yellow leavesThe flowers become phylloid.Branches and shoots of infected treesusually showed die back in the current year and it might be affect itsgrowth rate in the following years.Typical symptom appeared on healthy seedling by graft-inoculationwith diseased barks.Mycoplasma-like bodies could be seen in the se-veral elements of phloem tissue under electron microscope.The unit-membrane of MLO are 10 nm thick and are 200-820 nm in diameter.They are spherical and ellipsoidal.Most of the seedling derived fromthe diseased root-cutting are able to produce witches′broom.The disea-se could not be transmitted by sap inoculation or through seed.Diseased root-cuttings should dip in hot water between 40℃ and 50℃for 30 minutes,or in 1000 ppm tetracycline in water before plant.These methods could effectively control the disease for several years.Inject 10000 ppm of tetracycline in water or 5% sodium borate intothe diseased trunk or soaked by its root would reduce the develop-ment of the disease in some extents.更多还原