POST-HARVEST CONTROL OF APPLE BLUE MOLD UNDER COLD STORAGE CONDITIONS

Abstract

To control blue mold of apples caused by Penicillium expansum after harvest and during commercial cold storage, microwave exposure was investigated as a physical measure and compared with the use of calcium chloride and the systemic fungicide, carbendazime. Microwave exposure of Golden Delicious and Royal Gala apples at 2450 Mhz for 10, 30 and 45s was effective as 4% CaCl₂ and carbendazime on significantly reducing the disease incidence %. Calcium chloride was more effective at 8% than 4% or at 1% and was as effective as carbendazime in reducing the mold severity and incidence. Microwave exposure for 10, 30 and 45s was as effective as 8% CaCl₂ and carbendazime on controlling blue mold caused by P. expansum stored under the conditions of commercial cold storage. Different apple cultivars have different degrees of susceptibility to the blue mold. Granny Smith and Red Delicious were relatively more tolerant than Golden Delicious, Starking or Royal Gala. However, sight variations were found in their responses to different treatments. Therefore, 10-45s microwave exposure of apple fruits before cold storage alone or in a combination with other methods can be an environmental safe physical alternative to chemical fungicides for controlling P. expansum infections during cold storage.