Isolation, characterization and control of canker disease causing bacteria of selected citrus plants in Rajshahi, Bangladesh
Arnaba Saha Chaity, ME Khan Chowdhury, Md. Faruk Hasan, Md. Asadul Islam, Md. Fazlul Haque, Biswanath Sikdar
Xanthomonas axonopodis pv. citri is responsible for the overwhelming important disease of citrus known as citrus canker. Isolated bacteria were characterized by different physical, biochemical, carbohydrate utilization and vitamin C tolerance test. The result of vitamin C tolerance revealed that all three isolates had the ability to tolerate higher level of vitamin C as compared with that of Rhizobium indicating that vitamin C is less toxic to canker bacteria. Optimum temperature and pH for growth of isolated bacteria were 28 0C and pH 7. The isolates showed similar morphological and biochemical characteristic that confirm the identity of isolates as belonging to those of Xanthomonas axonopodis pv. citri. Isolated bacteria were gram negative, rod shaped, motile and highly sensitive to Ciprofloxacin (29.0±0.00mm diameter of zone of inhibition). However, isolated bacteria X1, X2 and X3 wererespectively highly sensitive to extract of Spondia mombin (23.0mm/30μl) , Lawsonia inermis (20.0mm/100μl)and Candle bush (25.0mm/30μl)respectively. The highest antagonistic activity was found by soil borne bacterial isolates D, A & B and A against the isolated bacteria X1 (10.0±0.0mm zone of inhibition), X2 (14.0±0.0mm zone of inhibition) and X3 (13.0±0.0mm zone of inhibition) respectively. The results reveal that the isolated X. axonopodis contain unique characteristics which are vital for better understanding about local type of citrus canker disease as well as for designing locally effective control measures of this notorious disease.