A review of the occurrence, biology and management of common bacterial blight

Abstract

Common bacterial blight caused by Xanthomonas axonopodis pv. phaseoli (Xap) has been reported in many countries of the world. The disease is prevalent in areas that experience warm weather conditions, causing up to 40% yield reduction. Xap grows on a number of different media producing colonies that are yellow, mucoid and convex. The bacterium is single celled and motile by means of a polar flagellum. Besides infecting Phaseolus vulgaris, Xap also attacks other legumes like Glycine max and Dolichos lablab. It is capable of epiphytic survival on both leguminous and non-leguminous plants like Chenopodium album, Solanum nigrum, Zea mays and Amaranthus retroflexus. The disease causes symptoms to appear on leaves, stems, flowers and seeds. The pathogen can survive in seeds for up to fifteen years, and is also known to overwinter in crop debris. Seed infection is the primary means by which the pathogen spreads. Therefore, the production and use of certified seeds is one control measure that is effective in dealing with the disease. Besides, there are chemical and cultural control options available in the management of common bacterial blight.