白绢病是兰花世界性病害之一。该病在春夏之交的梅雨季节,以及秋雨连绵时发生尤为严重,主要为害兰花的根部及茎基部分。初发病时,在兰叶基部接近土壤处出现水渍状黄色病斑,后迅速扩展至根部,随后叶片萎蔫、茎杆呈褐色腐烂,容易折断。严重时兰花假鳞茎也会被侵染,在病部产生白色绢丝状菌丝,呈辐射状延伸,并在根际土表蔓延。 Sclerotium is one of the orchids in the world. The disease occurs during the rainy season at the turn of the spring and summer, and especially when autumn rains occur. The disease mainly affects the root and stem base of orchids. At the initial onset, watery yellowish spot appeared on the base of the leaf near the base of Lanzhou, and then rapidly spread to the roots. The leaves then wilted, the stems were brown and decayed easily. In severe cases, the orchid pseudobulb will also be infested, resulting in a white silk mycelium in the diseased part, extending radially and spreading in the rhizosphere.