Suppression of Bacterial Leaf Blight (Xanthomonas oryzae pv. oryzae) using Local Isolates of Rhizobacterial Antagonists

Abstract

Local isolates of rhizobacteria associated with rice rhizosphere were evaluated against Xanthomonas oryzae pv. oryzae (Xoo) both in vitro and in vivo conditions. Twenty-three rhizobacteria were isolated from the rice-growing provinces of Caraga Region, Philippines, and their antagonistic activity were evaluated against Xoo causing bacterial leaf blight (BLB) on rice using well diffusion assay method. Among the isolates evaluated, three (FVP 08, FVP 09, and FVP 22) were found highly antagonistic against the test pathogen with a clear and strong degree of the zone of inhibition. The three rhizobacterial antagonists were further evaluated for biological control against Xoo under greenhouse condition. The application of these rhizobacterial antagonists on inoculated rice plants showed shorter lesion length, effectively suppressed the bacterial leaf blight and managed to reduce the severity of BLB.