木麻黄是我国南方沿海地区用作防风固沙、用材以及行道树的优良树种之一。但是,由于丛枝病的发生,对这一树种造成严重危害。丛枝病在木麻黄的各个生长时期均可发生,但以苗期为甚。据肇庆、新兴、惠东、清远等市、县的调查,苗期感染率均在80%以上。该病害的症状是:病苗明显矮化,小枝节间缩短,不定芽提前萌发成丛生状;病发后期,病苗黄化并往往枯萎死亡,以致出圃率极低。1983年,我们通过对病组织超薄切片检 Casuarina is one of the fine tree species used as windbreak and sand fixation, timber and sidewalk trees in the southern coastal areas of China. However, due to the occurrence of the brouch disease, this tree species is seriously endangered. Broussoneses can occur in all growth stages of Casuarina, but the seedling stage is very serious. According to Zhaoqing, emerging, Huidong, Qingyuan and other cities and counties survey, the infection rate at seedling stage are more than 80%. Symptoms of the disease are: dwarf disease significantly dwarf, shorten the internode, adventitious buds premature germination into clusters; late disease, the disease is yellowing and often withered death, resulting in a very low rate. In 1983, we passed the ultra-thin biopsy of the diseased tissue