Assessment and characterization of mung bean (Vigna radiata) bacterial brown spot in Eastern Amhara, Ethiopia

Mung bean is one of the major early maturing pulse crop grown all over the world including Ethiopia.  The production of the crop in Ethiopia, however, suffers from many diseases caused by bacteria. The study aims to assess the intensity and identify the major foliar bacterial and fungal pathogens of the crop. Purposively, 3 districts and randomly 90 mung bean fields were surveyed during the study period. Pathogenicity test, macroscopic and microscopic observations and biochemical tests were used for identification. Symptomatic of 33 diseased bacterial samples were initially isolated and purified on nutrient agar. Bacterial brown spot was found as important foliar devastating identified diseases, even if its distribution varied among localities. Water soaked, small, circular, brown lesions surrounded by yellow zones were observed in all bacterial brown spot isolates after 8 days of inoculation. Based on cultural and biochemical characteristics, bacterial isolates were identified as grams negative phytopathogenic bacteria called Pseudomonas syringae pv. Syringae. However, further characterization of both isolates and phenotypic characteristics of a large population of newly emerged P. syringae pv. Syringae from various host plants should capture the research attention. This is the first report on the occurrence of such disease in Ethiopia. Key words: Bacterial brown spot, distribution, Eastern Amhara, identification.