THE in vitro POTENTIAL OF BANANA RHIZOBACTERIA IN CONTROLLING Phyllosticta cavendishii

The Freckle disease caused by Phyllosticta spp. in bananas have been documented for a long time. To date, chemical pesticides have been the main approaches for controlling the Phyllosticta diseases. Meanwhile, rhizobacteria can antagonized many fungal phytopathogens and have been applied as biocontrol agents of diseases in many crops. Some papers have proved that microorganisms can inhibit in vitro Phyllosticta spp. and control Phyllosticta spp. diseases on crops. The aim of this study was to evaluate the ability of banana rhizobacteria as biocontrol agent for P. cavendishii. In this study, bacterial antagonists were isolated by using P. cavendishii as selective agent in potato dextrose agar. The results showed bacterial antagonists inhibiting P. cavendishii widely distributed in banana rhizosphere. The BE165 strain was screened from 46 collected antagonistic isolates by the dual culture technique and was identified to be closely related to Bacillus atrophaeus. based on the matrix-assisted laser desorption/ionization technique and the time-of-flight analyzer. This strain could use the broth containing only ripe Cavendish banana fruit extract for the growth. Notably, the BE165 subcultures still exhibited the antagonistic activity in inhibiting P. cavendishii on agar dish. It was clearly that the rhizobacteria was potential biocontrol agents for the pathogenic P. cavendishii on banana.