The Potential of Pseudomonad fluorescens Secondary Metabolites to inhibit Ralstonia solanacearum Bacterial Wilt Disease

This study aims to determine the ability of Pseudomonad fluorescens isolates Pf-122 and Pf-142 secondary metabolites against R. solanacearum pathogen in vitro and in vivo. The study used a two-factor factorial experiment with RAL design and the observed data were analyzed using the Least Significant Difference (LSD) of 5%. The first factor was the type of isolate of Pseudomonad fluorescens: P1 (Pf-122) and P2 (Pf-142). The second factor was the concentration of the secondary metabolites: K1 (10%), K2 (20%) and K3 (30%), so six treatments were done and repeated five times. The in vitro results indicated all treatments could weakly inhibit R. solanacearum development indicated by the small inhibition zone. This may be due to the presence of siderophore antibacterial compounds; pioverdin, pioluteorin, HCN and phenazine. This study observed the largest inhibition zone in P2K3 treatment (Pf-142, 30%). The in vivo antagonist test indicated that all treatments could suppress bacterial wilt disease. The disease index was 0% for 4 weeks of observation while it reached 57.33% in control.