Abstract: Compositions for the treatment/prevention of microbial diseases of fruit comprising an effective amount of at least one yeast strain selected from the species Rhodotorula glutinis (Fres.) Harrison and Rhodotorula mucilaginosa (Jorg.) Harrison; optionally in association with one or more agriculturally acceptable carriers or excipients are described, as well as methods involving the same. Compositions may be applied to fruit either pre-harvest or post-harvest with post-harvest treatment being preferred. Microbial diseases of fruit which may be treated include blue mold, grey mold, mucor rot and transit rot of fruit.