Application of Candida saitoana and glycolchitosan for the control of postharvest diseases of apple and citrus fruit under semi-commercial conditions

The efficacy of the combination of Candida saitoana with 0.2% glycolchitosan (the bioactive coating) as a biocontrol treatment of postharvest diseases of apple and citrus fruit was evaluated in tests with natural inoculations that simulated commercial packinghouse conditions. The growth of C. saitoana in apple wounds and on fruit surfaces was not affected by glycolchitosan. The bioactive coating was more effective in controlling decay of several cultivars of apples (Red Delicious, Pome, Golden Delicious, and Empire) than either C. saitoana or 0.2% glycolchitosan alone. Depending on the apple cultivar used, the bioactive coating was comparable or superior to thiabendazole in reducing decay. The bioactive coating was also superior to C. saitoana in controlling decay of oranges (cvs. Washington navel, Valencia, Pineapple, and Hamlin) and cv. Eureka lemons, and the control level was equivalent to that with imazalil. The bioactive coating and imazalil treatments offered consistent control of decay on Washington navel oranges and Eureka lemons in early and late seasons, while C. saitoana or 0.2% glycolchitosan were most effective on early-season fruit. The combination of C. saitoana with 0.2% glycolchitosan also reduced the incidence of stem-end rot of cv. Valencia oranges, but control was less effective than treatment with imazalil.