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Poster: Biology & Disease Mgmt: Biological Control


Inhibition of Penicillium expansum growth on Golden Delicious apples by wild yeasts from various plant materials

Wild yeast strains previously isolated from various fruits were tested for their ability to inhibit Penicillium expansum in vivo (on Golden Delicious apples) in an effort to determine their potential as biocontrol agents (BCAs). Tests were performed at room temperature (~21oC) for up to 2 weeks and at refrigeration (3oC) for up to 2 months. Candida oleophila was used as positive BCA control. All strains tested showed some degree of biocontrol activity against P. expansum. At room temperature, activity (lesion size reduction) ranged between 37 and 50% during the first week. After 14 days of incubation, decays on yeast-treated apples were slightly smaller (16-19%) than those on apples treated with P. expansum alone. At refrigeration, lesion reduction ranged between 54 and 76% in the first month of storage and between 60 and 76% after 2 months of incubation. Decay incidence was 100% in apples stored at room temperature and 25-62% in those kept under refrigeration. The inhibitory activities of the wild yeasts were similar to those exhibited by C. oleophila. These strains showed potential as BCAs against P. expansum on stored apples.