Improved Control of Apple and Citrus Fruit Decay with a Combination of Candida saitoana and 2-Deoxy-D-Glucose

Abstract

A combination of Candida saitoana with 0.2% 2-deoxy-D-glucose to control decay of apple, lemon, and orange fruit was evaluated. Growth of C. saitoana in vitro was reduced by 2-deoxy-D-glucose; however, in apple wounds, the yeast grew as well in the presence of 2-deoxy-D-glucose as in its absence. When applied to fruit wounds before inoculation, the combination of C. saitoana with 0.2% 2-deoxy-D-glucose was more effective in controlling decay of apple, orange, and lemon caused by Botrytis cinerea, Penicillium expansum, and P. digitatum than either C. saitoana or the application of a 0.2% solution of 2-deoxy-D-glucose alone. Increasing the concentration of 2-deoxy-D-glucose from 0.2 to 0.5% did not improve control significantly. The combination of C. saitoana with 0.2% 2-deoxy-D-glucose was also effective against infections established up to 24 h before treatment. When applied within 24 h after inoculation, the combination of C. saitoana with 0.2% 2-deoxy-D-glucose was very effective in controlling blue mold of apple and green mold of orange and lemon. The level of control of green mold was equivalent to imazalil treatment. When either C. saitoana or 0.2% 2-deoxy-D-glucose was applied within 24 h after inoculation, neither had an effect on disease development on apple, orange, or lemon, and the incidence of decay was similar to the water-treated control.