Characterization of leaf blight pathogen, Pseudomonas syringae pv. syringae of mango in Bangladesh.
Islam S. I. A., Islam M. R., Dastogeer K. M. G., Hossain I.
Author Affiliation: Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh.
International Research Journal of Biological Sciences 2 : 39-45
Abstract : Bacterial leaf blight of mango caused by Pseudomonas syringae pv. syringae is an emerging disease and great threat for production of healthy mango saplings in different nurseries of Bangladesh. A survey was conducted in nurseries of some selected areas viz. Dinajpur, Rajshahi, Khulna, Mymensingh and Madhupur of Bangladesh to know the status of bacterial leaf blight of mango in terms of its incidence and severity and to characterize the pathogen causing the disease. The results showed that the highest (10.42%) bacterial leaf blight incidence was recorded in Rajshahi followed by Mymensingh, Madhupur and Dinajpur with 9.73, 9.12, 8.64% disease incidence respectively and the lowest (8.58%) incidence was recorded in Khulna. The maximum (7.34%) severity of bacterial leaf blight was recorded in Rajshahi followed by Dinajpur, Mymensingh and Madhupur with 7.17, 7.13, 7.13% disease severity and the minimum (7.03%) severity was recorded in Khulna. Twenty four bacterial isolates were obtained from the infected leaves by tissue planting method from different locations surveyed. Pathogenicity test on detached mongo leaves confirmed the bacterium was Pseudomonas syringae pv. syringae. The hypersensitivity test in tobacco leaves with P. syringae pv. syringae isolates did not show rapid death leaf of tissues where infiltrated. The causal bacterium, P. syringae pv. syringae was also characterized by a series of biochemical tests viz. KOH solubility test, Gram staining test, Kovac's oxidase test, Temperature sensitivity test, Levan test, Sugar utilization test, Arginine dihydrolase activity, Catalase test and Pectolytic test. The results of the all the tests revealed that the causal organism of leaf blight of mango was Pseudomonas syringae pv. syringae.