Antagonistic properties of two bacterial biocontrol agents of grey mould disease

Bacillus pumilus NCIMB 13374 and Pseudomonas fluorescens NCIMB 13373 inhibit the growth of Botrytis cinerea, the cause of grey mould of strawberries. Both antagonists increased the pH of the growth medium from pH 6 to pH 8-8.5 and both produced antifungal agents. The compound(s) produced by B. pumilus had a fungicidal effect during conidial germination, whereas the compound(s) produced by P. fluorescens had a fungistatic effect. There was no evidence for the production of inhibitory volatile compounds. Both isolates also showed the ability to inhibit other strawberry fungal pathogens, and have potential for a wider range of biocontrol of plant diseases.