Abstract

Blood disease bacterium (BDB) causes major decline of banana plants in many places throughout Indonesia. The cultural and biochemical characteristics of BDB isolates are very similar to those of Ralstonia solanacearum race 2 that causes Moko disease. Therefore, this study aimed to find a simple method for differentiating isolates of BDB from R. solanacearum race 2 of banana by testing their capability to liberate phage. BDB were cultured on sucrose-peptone agar, killed with chloroform vapour then overlaid with agar seeded with indicator strain R484 (R. solanacearum race 2). Twenty-two isolates of BDB from new outbreaks of banana blood disease from Central Java and West Nusa Tengara Provinces and 16 isolates of R. solanacearum race 2 from several countries were tested. All 22 isolates of BDB, but none of the R. solanacearum isolates, were lysogenic, indicating that lysogeny is a highly specific property of BDB and can be used to differentiate BDB from R. solanacearum race 2. The test is simple and can be performed in the laboratory with basic equipment.