粗肋草細菌性軟腐病的化學及生物防治之初步探討

Preliminary tests for chemical and biological control of bacterial soft rot of Aglaonema

粗肋草（Aglaonema spp.Schott）為台灣重要的外銷觀葉植物，栽培地區主要分佈於高雄縣及屏東縣內。台灣目前已知的粗肋草病害，包括由Colletotrichum gloeosporirids(Penz.) Sacc.引起的炭疽病及由Phytophthora meadii McRae及P. parasitica Dastur引起的疾病，病毒病害則有芋頭嵌紋毒素病（Dasheen mosaic virus）。

"Aglaonema bacterial soft rot caused by Pectobacterium chrysanthemi in Taiwan has only been found on cultivar 'Sithiporn' in the field. Under environment conducive to the disease progress, the pathogen was able to infect more than 80 % of the Aglaonema cv. 'Sithiporn' plants in some major nurseries. When isolate ASR-3, a highly virulent strain of P. chrysanthemi isolated from A. cv. 'Sithiporn', was used to inoculate detached leaves of Oncidium sp. and Phalaenopsis sp. it could cause the same soft rot symptoms. This study was conducted to screen for biological control agents and chemicals against bacterial soft rot disease of Aglaonema. Sixteen strains of Trichoderma spp., Psuedomonas fluorescens OFP-7 and Bacillus subtilis (Tai-K Bacillus) were tested by using cellophane paper antibiotic method. Results showed that Trichoderma sp. T1 isolate and the fluorescent pseudomonad OFP-7 were inhibitory to the growth of ASR-3. When culture filtrates or spore suspensions were tested for disease control, OFP-7 and Tai-K Bacillus were able to prevent infection of detached leaves of Aglaonema by ASR-3, but could not stop the disease once infection occurred. Among the agrochemicals tested, none of the three copper chemicals could restrain the growth of ASR-3, but four antibiotics showed inhibitory effects. According to the results of detached leaves tests, thiophanate methyl plus streptomycin (500x and 1000x) showed better protection than other antibiotics. None of the antibiotics were therapeutic to the soft rot disease of Aglaonema."