Biocontrol efficacy of antagonist yeasts to gray mold and blue mold on apples and pears in controlled atmospheres

Biocontrol capability of the yeasts Trichosporon sp. and Cryptococcus albidus against Botrytis cinerea and Penicillium expansum was evaluated in apple (cv. Golden Delicious) and pear (cv. Jingbai) fruits at 1°C in air and under controlled atmospheres (CA) with 3% O₂ + 3% CO₂ or 3% O₂ + 8% CO₂. Trichosporon sp. controlled gray mold and blue mold of apple fruits more effectively than C. albidus (P < 0.05). Apple fruits treated with Trichosporon sp. and C. albidus had a lower incidence of gray mold rot than blue mold rot in the same storage conditions. Biocontrol efficacy of the yeasts for controlling gray mold and blue mold was better in apples than in pears. Populations of the yeasts in drop-inoculated wounds in fruits increased rapidly after 20 days at 1°C both in air and in CA conditions. There was no significant difference in colony diameters of the two pathogens cultured in 0 to 15% CO₂ concentrations after 7 days at 20°C, but the colony diameter of both B. cinerea and P. expansum at 20% CO₂ was significantly less than in other treatments (P < 0.05). CA with 3% O₂ + 8% CO₂ inhibited the pathogenic fungi more than CA with 3% O₂ + 3% CO₂.