摘要
胡蘿蔔酸腐病(sour rot)於1996年在傳統市場被發現，本省的胡蘿蔔在此之前尚無此病害之記載。病原經鑑定係Geotrichum candidum Link ex Pres.。病徵最初為水浸狀，至發病後期在感染部位會形成一薄層白色菌體，似乳酪狀，被害組織迅速崩解腐爛，並流出強烈酸味汁液。本病最適致病溫度為28 C，於20 C以下時發病程度減緩，於4 C以下時則無法發病。胡蘿蔔在相對濕度(RH) 100％與RH 75.5％之情況下，發病程度無顯著地(P=0.05)差異；但胡蘿蔔在15 C，RH 100％時發病率低，而RH 70.0％的條件下，幾乎不發病。得知此病原可在低濕度環境下生存，而且溫度為發病的主因。10 ppm之fenpropimorph和flutriafol即具有防治G. candidium之功效。從胡蘿蔔表皮上分離的拮抗菌，經對峙及共同培養篩選出Pseudomonas fluorescens #52 及Bacillus amyloliquefaciens #224菌株，均可造成本病原之菌絲變形、分支膨大、孢子凹陷及減少等現象，彼等均具減緩發病速率之效果。
並列摘要
In 1996, carrot sour rot was first found in the traditional market in Taipei. This disease was identified to be caused by Geotrichum candidum Link ex Pers. Carrot sour rot occurred mostly at the tip of the tap root. The early symptom was a water-soaked appearance on the infected tissue. A thin, cheese-like layer of white mycelium formed on the infected areas during the late stages of disease development. These diseased tissues were crumbly and rotted rapidly, exuding juices that smelled strongly sour. The optimal temperature for the disease development was 28 C. Below 20 C, disease severity was reduced. Carrot sour rot did not occur below 4 C. This disease occurred readily on carrot tissues under 28 C, regardless the relative humidity (e.g. 100% vs. 75.5%). While the storage condition was at 15℃, disease did not happen when the relative humility was 70%, and disease was mild when RH was 100%. This simply indicated that temperature was the critical factor to affect the development of carrot sour rot. 10 ppm of Fenpropimorph (75% a. i., Corrbel, Mistral) and flutriafol (12.5% a. i., Impact) were able to inhibit significantly the growth of G. candidum. Antagonistic microorganism isolates # 52 and # 224 were isolated from the surfaces of carrots and selected by means of dual and concomitant cultures. Both of them were able to cause the hyphae of G. candidum t o become deformed, besides this occurred clarifying and swelling on the affected hyphae. The amount of sporulation was also reduced significantly. The two antagonistic isolates (i.e. #52 and #224) were identified as Pseudomonas fluore s c e n s and Bacillus amyloliquefaciens, respectively, by BIOLOG system. They had the capability to reduce the disease severity in this test.