Biological Control of Ralstonia solanacearum Causes of Bacterial Wilt Disease with Pseudomonas putida and Streptomyces spp. on Some Tomato Varieties

Ralstonia solanacearum is one of the main pathogens in tomato plants that cause bacterial wilt disease. R. solanacearum in the field is difficult to control, because some phytopathogenic bacterial species produce EPS in large quantities. The practices of cultivation, soil fumigation and development of resistant varieties have been carried out as an effort to control these pathogens. Therefore, biological control is another alternative in controlling this pathogen. The research was conducted at the Plant Bacteriology Laboratory and in the Greenhouse of the Plant Protection Department, Faculty of Agriculture, Gadjah Mada University, Yogyakarta. In this study, the bacteria Pseudomonas putida strain Pf-20 and Streptomyces spp (isolates S-4 and S-16), 9 varieties of tomatoes and R. solanacearum were used. This study uses a Completely Randomized Design consisting of 3 treatments of biological control bacteria and 3 replications. The parameters observed were incubation time and disease intensity. Then also calculated the rate of disease progression and the value of the Area Under Disease Progress Curve (AUDPC). Data obtained were analyzed descriptively for all parameters ecxept incubation time was analyzed statistically. Statistical analysis data were then further tested with LSD at 5 level. Based on the results, the application of antagonistic bacteria can suppress the development of bacterial wilt disease. The best suppression of bacterial wilt disease development by biological control agents was seen in amelia and tombatu varieties. Further research is needed to observe the relationship between varieties and the ability of antagonistic bacteria to control R. solanacearum in tomato plants.