台灣的蘭花疫病

Phytophthora diseases of orchids in Taiwan

安寶貞(P. J. Ann)

《植物病理學會刊》 4卷4期 (1995/12) Pp. 152-162

https://doi.org/10.6649/PPB.199512_4(4).0002

摘要

在潮濕且管理不佳之蘭園中，蘭花極易罹患疫病，尤其是剛移出瓶的幼苗。目前已發現罹患疫病之蘭花種類包括:大蕙蘭(虎頭蘭)、小蕙蘭(報歲蘭、四季蘭、素心蘭、九華蘭、春蘭等)、蝴蝶蘭、嘉德麗蘭、石斛蘭、文心蘭、拖鞋蘭、萬代蘭、狐狸尾蘭及紅鶴蘭等。自罹病蘭花組織上分離得到之疫病菌有兩種，為Phytophthora parasitica 與P. palmivora。蘭花疫病之病徵可區分為三大類，(一)水浸狀斑：蝴蝶蘭、石斛蘭、文心蘭及拖鞋蘭等被害時，葉片、花器、假莖及新芽等部在初染病時出現水浸狀斑點，而後病斑擴大，除花器退色凋謝外，罹病部位呈暗綠色或淡褐色，組織雖然腐敗，有時仍十分堅硬，且不會被水解而潰爛，亦無惡臭氣味產生，但病勢會向上下部位蔓延擴展，造成葉片黃化脫落與全株萎凋枯死；(二)黑腐斑: 嘉德麗蘭以新芽、假莖較常染病，罹病部位之初期病徵為水浸狀，後期組織黑腐，呈暗褐色或黑褐色，病害並會向上下部位及葉片蔓延，導致全株死亡；(三)黃褐化及萎凋：蕙蘭屬以地下假球莖與新芽為主要受害部位，組織褐變，病害向根系與地上葉片蔓延，造成黃葉萎凋與全株死亡。蘭花在幼苗期極為感病，全株均可被疫病菌侵染：成株開花後，以幼嫩部位較為感病。接種試驗顯示，不經傷痍處理，疫病菌可直接侵入各種蘭花之花器、新芽與心菜，以及文心蘭與石斛蘭之葉片；但侵染大部分蘭花的成熟葉片、假莖及根系時，則需要傷口。

關鍵字

蘭花 ； 疫病

並列摘要

Phytophthora attacked many cultivated orchid and caused serious in orchid production in Taiwan. Two species of Phytophthore were detected from the diseased tissue of 16 different orchids. The species of Phytophthore isolated from the infected orchids were P. parasitica on Phalaenopsis spp., Dendrobium spp., D. Phalaenopsis, Cymbidium sinense, C. ensifolium, and C. rybrugemmum, and P. palmivora on Phalaenopsis spp., Dendrobium spp., Cattleya spp., Oncidium spp., Paphiopedium spp., Vanda spp. Phaius spp., Cymbidium sp., C. owakensis, and C.formosanum. The pathogen produced three different kinds of symptom depending on different genus of orchids, AII affected orchids appeared water soaking spots on infected portions initially. However, the disease Iesions on phalaenopsis,dendrobiun, and oncidium developed rapidly and turned dark green or light brown, and the affected leave, became yellowing and dropped, and the whole plants died eventually. While P. palmivora induced typical 'black rot' symptoms on leave and pseudostems of the affected Cattleya on Cymbidium spp., Phytophthota spp. mainly attacked pseudostems and young buds, and cause yellowing, wilting, and death of the whole affected plants In pathogenicity tests, young orchid seedlings showed highly susceptible to Phytophthora The fungi could attack every portions of test orchid at the seedling stage without wounded treatment. The flowers, young leaves and buds of mature orchids were also very susceptible to the two pathogens However, wounds were usually required for infection of mature leaves and pseudostems of most cultivated orchids by spores of Phytophthora except dendrobium and oncidium. The artificially or naturally wounds caused by cuttings or induced by wind-brow-rains were the two main ways for penetration and dissemination of Phytophthora on orchids in natural fields.

並列關鍵字

Orchids ； Phytophthora parasitica ； P. palmivora