Ceratocystis paradoxa引起之可可椰子果實基腐病

Fruit Basal Rot of Coconut Caused by Ceratocystis paradoxa

曾勝志(S. J. Tzeng) ； 孫岩章(E. J. Sun)

《植物病理學會刊》 18卷2期 (2009/06) Pp. 67-74

https://doi.org/10.6649/PPB.200906_18(2).0002

摘要

可可椰子(Cocos nucifera L.)爲熱帶地區重要經濟作物，然而採收後鮮果實的儲藏問題，一直以來皆困擾著相關行業從事者。作者於2005年間，發現採自屏東縣九如、長治、內埔等地之椰子果實，在採收數日後，約2%自果頂或果實傷口出現果肉黑化、軟化之病徵，並散發特殊香味。自罹病果實內部可分離出一種有隔真菌，該菌於馬鈴薯葡萄糖瓊脂(PDA)平板培養基上之菌落初期爲白色、一至二天後變黑，且散發強烈水果香氣。該菌可產生兩種無性孢子，其一爲自長形壺狀產孢梗產出成長串之分生孢子，其孢梗大小爲80.0-155.0×5.0-7.8μm，分生孢子短筒至長筒形，大小爲8.5-16.0×4.7-6.7μm；另一爲菌絲末端特化形成之黑色卵形厚膜孢子，大小爲13.4-25.0×8.9-12.5μm。以分離所得菌株配對進行對峙培養，在兩個月後發現有一組產生淡褐色球狀子囊殼，大小約280μm，有長約1100μm之黑色長喙；其子囊孢子爲略彎梭形，大小12×3μm。依上述之形態特性，將此菌鑑定爲Ceratocystis paradoxa (Dade)C. Moreau（無性世代：Thielaviopsis paradoxa (de Seynes)Höhn)。將此分離菌株接種於椰子果實上，可產生與最初發現相同之病徵，並且可再分離得到相同之菌株。此病原菌菌絲最適生長溫度爲25-30℃，生長速度可達3.2cm/day，低於10℃或高於35℃時則幾乎不生長。此病原菌曾被報導可在椰子樹上造成樹幹流膠病(stem bleeding)與心芽腐敗病(bud rot)，另在1955年巴西曾報導可造成果實基腐病(fruit basal rot)，故本病以此命名，但本研究發現本菌不限於感染果蒂，亦可自其他傷口感染，故建議本病害亦可稱爲黑腐病(black rot)。在病害流行調查上，發現本病週年均可發生，但採收後開始發病之日數，則依時序而異。而在寄主範圍上，本菌株可在鳳梨果實上造成鳳梨黑腐病之病徵，故此二病害之病原應屬相同。

關鍵字

可可椰子 ； 果實基腐病 ； 採收後病害 ； Ceratocystis paradoxa ； Thielaviopsis paradoxa

並列摘要

Coconut (Cocos nucifera L.) is an important economic crop in tropical areas. Just like other fruits, the post-harvest diseases are big problems for farmers. Since 2005, coconut fruits harvested from Jiouru, Changjr, Neipu in Pintung county have showed a fruit rot disease. Principal symptoms are blackening of exocarp, mesocarp and then endocarp of coconut fruit. The affected fruit usually emitted fruit-type fragrant. A fungus was consistently isolated from the diseased fruits. Its colony on PDA plate was white in early stage but became black one or two days later. It emitred a strong fruity fragrance. This fungus produced two asexual spores. The first was phialospore-type conidia released in long chains from tip of long phialides. They were hyaline to mid-brown, cylindral to somewhat oval and thick-walled when mature, 8.5-16.0×4.7-6.7 μm. The phialide had the size of 80.0-155.0× 5.0-7.8μm. The second was chtamydospore formed in short chains from specialized hyphal tip, oval, black, 13.4-25.0×8.9-12.5 μm. Dual cultures of all paired isolates on PDA with one piece of coconut exocarp induced the production of perithecia. Perithecia were brown, glohose, 280 μm in diameter, with a 1100 μm long neck. Ascospores were ellipsoid, but some were unequally bent, 12×3 μm. According these characteristics, this fungus was identified as Ceratocystis paradoxa (Dade) C. Moreau (Anamorph : Thielaviopsis paradoxa (de Seynes) Höhn). Inoculation of all wild-type isolates on healthy coconut fruits reproduced the same black rot disease. The same pathogen was reisolated from the inoculated fruits. The temperature for hyphae growth of this fungus was 25-30℃, with the growth rate of 3.2cm/day. It cannot grow at temperatures lower than 10℃ or higher than 35℃. This pathogen was reported to cause stem bleeding disease in 2004 and bud rot disease of coconut in 1993, but a disease called fruit basal rot of coconut have been reported in 1955 in Brazil. With the same pathogen, we suggest this newly found disease can be also named as black rot. This disease occured on coconut fruits around all seasons, but is more serious in warm seasons, especially in the period from June to October. Disease incidence could reach 2% after 10 days of fruit storage. This black rot pathogen caused black rot disease of pineapple, while the pathogen from black rot of pineapple also caused black rot of coconut fruit, indicating that both diseases have the identical pathogen.

並列關鍵字

coconut ； fruit basal rot disease ； post-harvest disease ； Ceratocystis paradoxa ； Thielaviopsis paradoxa