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苦楝(Melia azedarach L.)是南方农村宅旁、路边绿化的优良树种。在浙江、福建、广东等省均有成片栽植。浙江省临海县曾有大批苦楝树,从七十年代开始遭到丛枝病危害,1975—1978年发病最为严重,到七十年代末,素有“苦楝之乡”之称的临海县已很少有苦楝残存。苦楝丛枝病症状是属于典型的植物黄化病害症状。由于顶芽生长受阻,出现了腋芽和不定芽大量萌发,节间缩短,形成严重的丛生症状;严重时在枝梢上丛枝及病叶簇生成团,病叶黄化变小,病叶缩小成健叶的五分之一,有的甚至变成线状。丛枝症状往往从个别枝梢逐渐发展至所有枝梢,小树大
Melia azedarach L. is a good tree species in the south side of residential houses and roadside greening. In Zhejiang, Fujian, Guangdong and other provinces have Chengcai planted. Linhai County, Zhejiang Province, there have been a large number of neem tree, from the seventies began to be withered branches disease, from 1975 to 1978 the most serious illness, to the late seventies, known as “Neem hometown,” said Linhai County is Juvenile few remaining. Symptoms of the neem bush disease belongs to the typical plant yellow disease symptoms. Due to the obstruction of the terminal buds, axillary buds and adventitious buds appeared a large number of germination, internodes shortening, the formation of serious clusters of symptoms; severe branches and diseased branches in the shoots cluster formation of diseased leaves yellowing smaller diseased leaves One-fifth into a healthy leaf, and some even become linear. Cong branch symptoms tend to gradually develop from individual shoots to all shoots, small trees