小花蔓澤蘭的白絹病

First Report of Sclerotium rolfsii on Mikania micrantha in Taiwan

傅春旭(Chuen-Hsu Fu) ； 鐘詩文(Shih-Wen Chung) ； 姚瑞禎(Jui-Chen Yao) ； 胡寶元(Bao-Yuan Hu)

《台灣林業科學》 18卷1期 (2003/03) Pp. 81-84

https://doi.org/10.7075/TJFS.200303.0081

摘要

小花蔓澤蘭(Mikania micrantha)在台灣已成具危害性的入侵植物。西元2000年夏天，台南縣廢耕農地上發現小花蔓澤蘭有突然枯萎的現象。最初期的病徵包括地基部的莖壞疽、葉片黃化及褐化。隨著莖部壞疽部位的增加，被感染植株最後枯萎死亡。倒伏與病死的組織覆蓋一層白色菌絲及褐色圓球形之菌核。利用0.1%(v/v)次氯酸鈉進行罹病組織表面消毒1 min後，再將罹病組織置於水瓊脂培養基中培養，可分離出白絹病菌(Sclerotium rolfsii)。利用盆缽培養的小花蔓澤蘭幼苗進行接種實驗來確認白絹病菌對小花蔓澤蘭的病原性。接種源包括菌絲及菌核兩種，接種時將接種源置於植株的莖基部，而未接種病原菌的植株作為對照組。所有實驗植株皆置於室溫中(24-30℃)觀察。接種植株在7d內表現出病徵，而未接種的植株未發現任何病徵。在被感染的組織上有菌核形成，並可分離出白絹病菌。白絹病菌雖可以感染許多種植物，但在小花蔓澤蘭則為台灣首次的病害紀錄。

關鍵字

小花蔓澤蘭 ； 白絹病菌 ； 白絹病

並列摘要

Mikania micrantha has recently become an invasive plant in Taiwan. During the summer of 2000, a M. micrantha plant which suddenly wilted was observed in a abandoned field of Tainan City, southern Taiwan. Initial symptoms included basal stemnecrosis, and yellowing and tan discoloration of the leaves. As stem necrosis progressed, the infected plants wilted and died. Necrotic tissues were covered with whitish mycelia which gradually developed reddish-brown, spherical (0.5 to 1 mm in diameter) sclerotia. Sclerotium rolfsii Sacc was consistently recovered from the surface of symptomatic stem parts that were disinfected for1mm in 0.1%(v/v)NaOC1 and then plated on water agar. The pathogenicity of 3 S. rolfsii Sacc isolates was confirmed by incoculating M. micrantha seedlings grown in pots. Inoculum consisted of mycelia and sclerotia of the pathogen which were placed on the soil surface around the base of each plant. Noninoculated plants served as controls, and all plants were kept in a high-moisture environment at room temperature(24-30℃) for disease development. Inoculated plants developed symptoms within 7 days, while control plants remained symptomless. Sclerotia developed on infected tissues, and the same fungus was reisolated from symptomatic tissues. Southern blight has been observed on many plants species, but this is the first record of M. micrantha southern blight caused by S. rolfsii Sacc in Taiwan.

並列關鍵字

Mikania micrantha ； Sclerotium rolfsii ； southern blight