Biocontrol potential of a Bacillus subtilis strain against Bactrocera oleae

Within the Mediterranean basin, pest infestation of the olive tree especially by Bactrocera oleae is a serious economic problem. In this study, we have isolated 115 bacterial strains from various ecological niches, and tested their ability to protect the olive fruits against Bactrocera oleae . Among these strains, culture supernatant (CS) of one bacterial strain displayed the highest rate of larval mortality, and was identified as Bacillus subtilis by 16S rRNA molecular analysis. Further characterization of the CS of the Bacillus sp. strain showed that the highest insecticidal activity against third instar larvae occurs at pH 7. Our results indicate that this bacteria strain may be a prospective alternative in pest control programs.