Effect of Different Storage Conditions of Apple Fruits on Colletotrichum Species Virulence

Abstract

Postharvest losses caused by phytopathogenic fungi can be severe, and low and high temperatures can significantly inhibit pathogen development from harvest to marketing. Colletotrichum spp. are important post-harvest pathogens of apple, causing losses from 30-80%. The losses are mostly managed by fungicide applications, as well as by keeping of fruits in adequate storage. Therefore, effect of different storage conditions (cold storage, ultra-low oxygen cold storage, storage at 35 degrees C) of apple fruits on Colletotrichum spp. virulence was studied in vivo, and compared with an effect of low and high temperatures on mycelial growth of the pathogens in vitro. It was found that both, high and low temperatures significantly affect pathogen development, in vitro and in vivo, and that high temperatures (35 degrees C) can completely inactivate virulence of C. acutatum, while low temperatures ( lt = 2 degrees C) can inactivate virulence of C. gloeosporioides. However, short-term storage of inoculted apple fruits at 5 degrees C can cause more pronounced virulence of both Colletotrichum species once they reach room temperature. According to the obtained results, combination of postharvest heat treatment with a long-term cold storage is proposed for complete elimination of Colletotrichum spp. on apple fruits.