苹果粗皮病的发病原因及症状观察

Factors Causing Occurrence of Rough Bark Disease of Apple Trees and Symptom Observation

试验表明,在盆栽条件下,施锰300mg/kg以下,树体生长发育正常,施锰400mg/kg以上发生生理性粗皮病,生物产量比对照低29%(达极显著水平),施锰600mg/kg的后期个别树死亡,施锰800mg/kg的后期大部分树死亡。生理粗皮病(internalbarknecrosis)是韧皮部中部分木质化组织在内部发生增生坏死而使得外表隆起,病瘤的发生部位不定。轮纹病的病瘤是病菌侵染后在皮下繁殖、扩展,形成了索状菌丝体结构,多数在皮孔部位发生。病枝离体后,生理粗皮病的病瘤不扩展,而轮纹病的病瘤很快扩展为褐斑瘤。生理粗皮病树的新梢叶片出现缺铁症状,轮纹病的不出现。

Experiments were conducted under potted grown conditions,2reasons causing occurrence of rough bark disease on apple stem were revealed and the symptoms were studied.Results showed that different concentration of Mn in soil pro-duced different effects on apple trees.It could accelerate the growth and development in the case of Mn concentration below300mg /kg.Physiological rough bark symptoms (IBN)appeared when the Mn concentration was over400mg /kg and the bi-ological output was29%lower than control.Several and a majority of apple trees died latter after applied Mn at concentra-tion of600mg /kg and800mg /kg.The proliferation and necrosis of certain tissue in the bark phloem caused the warts of in-ternal bark necrosis(IBN)on apple stem.The occurrence position of IBN on the surface of stem was not fixed.The infection of the fungus and the formation of rope-like mycelium under the cuticle caused the warts of ring rot(Botryosphaeria beren-griana f.piricola).The warts often occur on the lenticels.Thewarts of IBN did not expand when taken off the tree.However,in vitro warts of ring rot soon expand to large dark brown lesions.A deficiency symptom of iron appeared on the shoot of IBN-occurred trees other than the ring rot-occurred trees.