PREVALENCE OF Xanthomonas axonopodis pv. citri ON CITRUS CITRUS CANKER DEVELOPMENT

Abstract

Prevalence of Xanthomonas axonopodis pv. citri on citrus causing canker on citrus fruits transported from different districts of Bangladesh to the wholesale markets of Dhaka was studied during September 2012 to May 2014. Survey revealed that the highest incidence and severity of canker of citrus were recorded on the fruits transported from Chittagong in the month of September and May, respectively and the lowest incidence and severity were recorded on the fruits transported from Gazipur and Munshiganj, respectively in the month of January. A positive correlation was observed between the incidence and severity of canker with temperature, relative humidity and rainfall. The bacterium Xanthomonas axonopodis pv. citri was isolated from the canker infected part of citrus fruits and it’s morphological, biochemical and cultural features were studied. The bacterium was gram negative, rod shaped and showed positive results in KOH solubility test, starch hydrolysis test, catalase test, citrate utilization test, motility indole urease agar circular, small, flattened colonies on SX medium. Study on the effect of environmental factors on canker affected citrus seedlings indicated that leaf infection