臺灣地區由Stagonosporopsis cucurbitacearum所引起之苦瓜黑腐病及其防治藥劑篩選

Abstract

2016年夏秋（9月－11月）季節，於屏東的里港與萬巒及臺南東山地區，初期觀察到苦瓜果實上發生類似細菌性果斑病菌之褐色水浸狀病徵，後期病斑上可見黑色柄子殼產生。經由形態學觀察與分子生物學特徵，將其鑑定為Stagonosporopsis cucurbitacearum（Fr.）Aveskamp, Gruyter & Verkley（syn. Didymella bryoniae（Fuckel）Rehm），該菌被證實可引起多種瓜類的蔓枯病和果實的黑腐病或果腐病。本研究自罹病苦瓜果實分離之菌株SC04與SC10及葉片所分離之菌株SCl01，經病原性測試結果顯示，來自果實與葉部之S. cucurbitacearum菌株皆可在苦瓜果實引起黑腐的病徵，於葉片和莖部則可造成褐色水浸狀病斑。此外，SCl01、SC04及SC10菌株對6種不同瓜類之寄主範圍測試，結果顯示供試菌株皆可在所有測試植株上造成水浸狀病斑，然其中又以胡瓜（秀綠）、西瓜（甜美人）、甜瓜（銀輝）及洋香瓜（秋香）病徵表現較嚴重。進一步測試該病原菌對不同藥劑之感受性，結果指出目前推薦於防治瓜菜類病害之藥劑中，以賽福座的效果最佳，而四氯保淨次之，於培養基上對病原菌菌落之生長抑制率均可達70%以上，可提供農民防治苦瓜黑腐病之參考。 During summer to autumn of 2016, the fruit of balsam pear (Momordica charantia L.) with brown and water-soaked lesions was observed in Pingtung and Tainan in Taiwan. At later stage, blackish pycnidia were observed on old lesions of the diseased fruits. The pathogen was identified as Stagonosporopsis cucurbitacearum (Fr.) Aveskamp, Gruyter & Verkley (syn. Didymella bryoniae (Fuckel) Rehm) based on morphological and molecular characteristics. The fungus caused gummy stem blight on stems and black rot on the fruits. In this study, the SC04 and SC10 isolated from black rot fruits and SCl01 isolated from leaf spot infected fruit, leaf and stem of balsam pear in pathogenicity tests. Moreover, six cucurbit cultivars were susceptible to SCl01, SC04 and SC10 isolates, in which watermelon, cucumber, muskmelon and orient melon showed severe symptom on stems. Moreover, in screening of the fungicides for controlling the black rot, triflumizole was found to be able to inhibit the colony growth effectively.