云南河口香蕉黄化束顶病研究——Ⅰ.症状与发病规律

ON BANANA YELLOW BUNCHY-TOP DISEASE OCCURRING IN HEKOU, YUNNAN PROVINCE I . SYMPTOMS AND DEVELOPMENT

作者通过连续六年的田间定点调查与研究认为发生在云南河口及其邻近县市香蕉上的黄化束顶病不同于已往记载的BBTV所致的香蕉束顶病。病株新抽叶短小、窄、叶缘失绿黄化或整叶白化;假茎外表面紫红色;果穗从假茎中不能或部分抽出;根部着生根结。病株地上部发病高峰表现在植株进入快速生长而原根系已腐烂、新根尚未形成的春季,而夏末秋初为根结形成高峰。健株根围接种根结线虫后表现典型的黄化束顶症状。田间增施氮肥加重发病,香蕉宿根年限越长病情愈重。连作地、熟地、旱作地分别较轮作地、荒地以及低洼稻作地的发病率高。部分病株进入雨季或移植长期隔置的香蕉土壤中能恢复正常生长。病害的自然传播与土壤密切相关。

This paper deals with the symptoms and field development pattern of banana yellow bunchy-top disease occurring in Hekou, Yunnan Province. The disease is significantly different from BBTV-caused banana bunchy-top disease. The newly sprouted leave o[ diseased plants become small and yellow along leaf edge or almost white with the whole leaf. The outsurface of pseudostem becomes purplish red. Infructescence sprouts partially or even does not. Root-knots caused by Meloidogyne sp. are usually observed on diseased plants. The above-ground symptoms appear throughout the year with a peak from February to March, but the root-knot appears in summer and autumn with a peak from June to August. The disease incidence increases with the longevity of perennial roots and with the addition of nitrogen to around crop roots. It is also higher in continously cropping banana soils than in crop rotation soil, in cultivated land than in uncultivated land, in moderate moisture soil than in well drenched low-lying land. Some diseased plants transferred to healthy soil can recover their growth vigor without symptoms. The field spread of disease in nature is associated with soil.