Antagonistic action of Bacillus sp. AB89 to Phloeospora maculans, causal agent of mulberry leaf spot

The control of mulberry leaf spot caused by the infection of Phloeospora maculans (Septogloeum mori) has been important for sericulture in Goto islands. Since the chemical control of this leaf-spot disease was not available except for off-season, the possibility of other kind of control measure was tested. Phylloplane bacterium Bacillus sp. AB89 from a rice leaf was quite useful as an antagonist. Culture filtrate of the antagonistic bacterium inhibited spore germination and mycelial growth of leaf spot pathogen. Furthermore, the culture filtrate and living bacterial cells limited distinctly the development of lesions on mulberry leaves in vivo.