THE SURVIVAL OF XANTHOMONAS CAMPESTRIS PV. MUSACEARUM IN SOIL AND PLANT DEBRIS

The survival of Xanthomonas campestris pv. musacearum (Xcm), the cause of banana bacterial wilt disease in soil and infected banana debris was investigated. Viable cells of the pathogen were estimated on culture medium. The survival of the pathogen in soil was influenced by soil moisture and soil treatment. The survival period of Xcm was reduced 3 times when soil moisture content was reduced from 28% to 14%. Soil treatment impacted on the survival of Xcm, with populations declining rapidly in non-sterile soil than in sterile soil. No viable cells of the pathogen were recovered from non-sterile soil after 20 days under both high and low soil moisture contents. Viable pathogen cells survived for slightly a longer period in soil in the field than non-sterile soil under controlled conditions. In sterile soil the pathogen cells persisted for up to 90 and 45 days under high and low moisture soil respectively. Populations of Xcm in debris in the field declined rapidly, with no pathogens cells recovered after 21 days but the viable cells remained stable in the laboratory throughout the 90 days of sampling. Results indicate that Xcm has limited ability to survive saprophytically in soil and plant debris in presence of other competing microoganisms. This implies that bananas can be replanted in fields where the crop was previously destroyed by Xcm in a relatively short period of time.