Evaluation of the use of high CO₂ concentrations and cold storage to control Monilinia fructicola on sweet cherries

Growth of Monilinia fructicola significantly declined with increased CO₂ concentration, both in vitro and in vivo. CO₂ concentrations at 15-25%, provided a significant reduction in lesion size and, at 30%, completely prevented lesion formation at 25°C. Low temperature also inhibited growth and pathogenicity of M. fructicola. The fungus was more sensitive to high CO₂ concentrations at 0°C. Fungal growth on PDA was completely suppressed and brown rot was not found in inoculation sites on fruits in 10-30% CO₂ after 30 days at 0°C. Low temperature reduced ethylene production more than elevated CO₂. Fruit ethanol content increased with increasing CO₂ concentration and reached 92.8 μl l^-1 in 30% CO₂ after 18 days at 0°C. CO₂ concentration of 25-30% did not affect SSC and pH, but increased firmness, vitamin C content and titratable acidity. No high CO₂ injury or off-flavors were noted after 18 days at 0°C for sweet cherries at any CO₂ level tested.