行政院農業委員會台南區農業改良場   研究彙報第50號

 

木瓜黑腐病之研究

鄭安秀、吳雅芳、郭源燿、黃淑惠

摘  要

鄭安秀、吳雅芳、郭源燿、黃淑惠•2007•木瓜黑腐病之研究。台南區農業改良場研究彙報:50:24 - 30。 本研究室於2006年元月起分別由台南縣玉井鄉、大內鄉、嘉義縣中埔鄉及雲林縣林內鄉木瓜栽培區採集罹病葉、莖及果實,共分離純化得15個木瓜黑腐病病原細菌菌株。田間觀察,罹病植株葉片黃化後落葉,黃化葉柄橫切面可見褐化維管束,有菌泥泌出;病原細菌可於莖部維管束上、下蔓延,造成更多黃化落葉、株心黑腐及果梗腐爛落果。病原細菌於NA培養基上呈現乳白色菌落,菸草葉肉接種24小時後呈現過敏性反應。將病原細菌調製成108cfu/ml之細菌懸浮液,均勻噴霧於木瓜苗,接種後3-4天植株葉背即出現水浸狀斑點,斑點漸擴大、癒合,葉片捲曲、下垂、萎凋。病原細菌由莖部維管束往上蔓延至株心部,呈現水浸狀後變黑進而壞死,亦往下蔓延至地際部及根部。將一個月大之木瓜苗種植於混合病原細菌之介質中,病原細菌可由根部感染木瓜苗。病原細菌於25至30℃下可正常生長。利用濾紙圓盤法及液體培養法於實驗室中進行藥劑篩選,結果顯示抑菌效果以85%鹼性氯氧化銅可濕性粉劑、20%歐索林酸可濕性粉劑、68.8%多保鏈黴素可濕性粉劑及10%鏈四環黴素可溶性粉劑較佳。以噴霧接種於木瓜幼苗後施藥,初步結果顯示,第三次施藥後18天,20%歐索林酸可濕性粉劑1000倍稀釋液、10%鏈四環黴素可溶性粉劑1000倍稀釋液及81.3%嘉賜銅可濕性粉劑1000倍稀釋液處理的罹病度較無藥劑處理為低,達顯著性差異。但穿刺接種後施藥,則供試藥劑均無防治效果。 關鍵詞:木瓜黑腐病、Erwinia sp. 接受日期:2007年12月26 日


Studies on Black Rot of Papaya


Cheng, A. S., Y. F. Wu, Y.Y. Kuo and S. H. Huang


Summary

Fifteen strains of Erwinia sp. were isolated from papaya leaves with black rot in Tainan, Chiayi and Yulin counties in 2006. Typical symptoms of black rot in the field include yellowing and wilting of infected leaves, browning of vascular bundle, black rot on top of stem tips and fruits. The bacterial colony is white on NA medium and it grows best between 25 and 30℃. Hypersensitive reaction was found 24hrs after inoculation on tobacco leaf. Water-soaking spots appeared in the back of papaya leaf 3-4 days after spraying inoculation with 108cfu/ml bacterial suspension, followed by leaf wilting. The bacterial spread in the vascular tissue up to stem tip and down to the root. The pathogen is able to infect papaya seedlings in muck soil with pathogen. Fungicide trials showed that Copper oxychloride, Oxolinic acid, Atakin and Streptomycin hydrochloride +Tetracycline were able to inhibit the growth of the pathogen in vitro tests in the laboratory. Green house test showed that Oxolinic acid, Streptomycin hydrochloride+Tetracycline or Kasugamycin hydrochloride+Copper oxychloride were able to reduce disease index in the plants by spraying inoculation, but not in the plants with needle-stick inoculation.
Key words:Black Rot of Papaya、Erwinia sp.
Accepted for publication:26 December, 2007


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