番木瓜白粉病病原鉴定·发生原因及防治策略

目的]为番木瓜高产优质栽培提供依据。方法]对云南种植区番木瓜白粉病的病原菌进行了鉴定,并对其危害症状、发生和流行因素进行了观察和分析。结果]番木瓜白粉病病原菌无性世代属半知菌亚门、丝孢纲、丝孢目,其子实层呈白粉状,分生孢子近椭圆形;该病主要危害番木瓜叶片、花芽,严重时也危害果实、果梗;番木瓜白粉病的发生和流行与气象条件关系密切,空气相对湿度低于25%时其分生孢子仍可萌发并侵入危害,分生孢子的最适萌发温度为20～25℃;栽培管理不当也是病害发生、流行的重要因素之一。结论]加强栽培管理,同时结合药剂防治可有效控制番木瓜白粉病的发生和蔓延。

Strategy on Pathogen Identification, Occurrence Reson and Control of Powdery Mildew in Papaw

Objective] The aim was to supply basis for high-yield and quality cultivation of papaw.Method] The pathogen of powdery mildew in papaw in Yunnan planting area was identified and its damaging system,occurrence and prevalence factors were observed and analyzed.Result] The asexual generation of powdery mildew pathogen in papaw belongs to Hyphomycetales of hyphomycetes in adelomycete subphylum.Its hymenium was white and powdery and the shape of its conidium was similar to oval.Its damaging symptom mainly occurred on leaves and flower buds of papaw and seriously,the fruit and fruit stalk would be damaged.The occurrence and prevalence of powdery mildew in papaw was closely related to meteorological condition.When the air relative humidity was lower than 25%,its conidium could germinate,invade and damage papaw.The optimum temperature for germination of conidium was 20-25 ℃.Unsuitable cultivation and management was also an important factor for the occurrence and prevalence of powdery mildew.Conclusion] The occurrence and spreading of powdery mildew in papaw could be controlled effectively by combining strengthened cultivation and management and fungicide application.