Control of bacterial wilt disease caused by Ralstonia solanacearum in ginger and postharvest treatment by antagonistic microorganisms.
Seventy-eight bacterial isolates and two commercially available microorganisms were evaluated for control of Ralstonia solanacearum racel biovar 4, a bacterium wilt disease pathogen of ginger in Thailand. Two bacteria, Bacillus subtilis K1 and Pseudomonas fluorescence PS12 and the commercially available fungus Trichoderma harzianum AP-001 (TrisanTM) provided the best disease control. In soil artificially infested with the pathogen and incubated in the laboratory, the three microorganisms reduced R. solanacearum population density after 9 days. In two greenhouse experiments, ginger plants were inoculated with R. solanacearum and then transplanted into soil containing powder formulations of B. subtilis K1, P. fluorescence, T. harzianum AP-001, or their combinations; the formulations were added at one tinge just before transplanting in the first experiment or in a split applications in the second experiment. The combination of P. fluorescence PS12 and B. subtilis K1 in a 1:2 ratio provided the highest level of control in both experiments; however, application once before transplanting provided lounger control than the split application. Post harvest treatments dipped with the bacterial combination at 5106 cfu/mL showed better control than the commercial T. harzianum AP-001 at the same concentration after dipped in a 1%w/v NaOCl in a long term protection from bacterial rot.