Morphological and Biochemical Characterization of Xanthomonas axonopodis pv dieffenbachiae (McCulloch & Pirone) Causing Bacterial Blight of Anthurium (Schott.)

Symptoms of bacterial blight of Anthurium bothunder natural and artificial conditions were studied. The typical symptoms such as initial water soaked lesions, development of necrotic area surrounded by yellow halo and flower and petiole infection were observed. In severe case pathogen become systemic in nature. The bacterial blight pathogen was isolated from infected leaves and purified by repeated streaking on Potato Sucrose Peptone Agar (PSPA) medium. The bacteria produced slimy yellow colonies and were aerobic gram negative rods. It produced acid oxidatively from sucrose, glucose, maltose, lactose, dextrose, fructose, sucrose, mannose and arabinose whereas no acid was produced from dulcitol, inositol, adinitol and sorbitol. It produced H₂S, liquefied gelatin and hydrolyzed starch. It utilized citrate, produced lipase and ammonia whereas it showed negative reaction for methyl red and urease test. Based on morphological and biochemical characters coupled with pathogenicity the pathogen was identified as Xanthomonas axonopodis pv. dieffenbachiae