Abstract Efficacy of a combination of Candida saitoana and 0.2% 2-deoxy- d -glucose as a treatment for the biological control of postharvest diseases of apple and citrus fruits was determined in semicommercial tests. The combination of C. saitoana and 0.2% 2-deoxy- d -glucose was more effective in controlling decay of ‘Rome’ and ‘Empire’ apples than C. saitoana alone, and the level of control was comparable or superior to that provided by the synthetic fungicide thiabendazole, depending on the variety used. In orange (‘Washington’ navel, ‘Hamlin’, and ‘Valencia’) and ‘Eureka’ lemon trials, the combination of C. saitoana and 0.2% 2-deoxy- d -glucose was also superior to C. saitoana for controlling decay, and the control level was equal to imazalil, especially on early-season fruits. On late-season ‘Washington’ navel orange and ‘Eureka’ lemon fruits, the combination of C. saitoana and 0.2% 2-deoxy- d -glucose was superior in controlling decay than C. saitoana alone, but control was significantly less than with imazalil. These results indicate the reliability and efficacy of the combination of C. saitoana and 2-deoxy- d -glucose for the control of postharvest diseases of apple and citrus fruits. Further tests under commercial conditions are needed to confirm these results.