Biological control of grey mould in strawberry fruits by soil Rhizosphere bacterial isolates

The goal of this study was to find effective bacterial isolates possessing antagonistic effects against <i>Botrytis cinerea</i> in strawberry in field conditions and to evaluate the antifungal properties of the extracellular metabolites produced by these isolates. Four bacterial isolates with considerable antifungal activity against <i>B. cinerea</i> were isolated from strawberries collected from local markets in Giza, Egypt. The molecular identification of bacterial isolates indicated that two of the isolates belong to the <i>Bacillus subtilis,</i> while the other two isolates belong to <i>Pseudomonas stutzeri</i>. The supernatants of the isolates were extracted and subjected to GC/MS analysis, which revealed that the supernatants of the isolates contained different types of fatty acids with expected antifungal activity. The most potent <i>B. subtilis</i> strain was further applied as a foliar spray over heavily infected strawberry fields, which led to significant reduction of <i>B. cinerea</i>. Therefore, this strain should be investigated further.