Postharvest diseases are generally difficult to control and are responsible for significant losses in crops of mango (Mangifera indica) and melon (Cucumis melo L.) in Brazil. The main postharvest pathogens of melon are Alternaria alternata, Fusarium pallidoroseum and Myrothecium roridum, while those of mango fruits are Colletotrichum gloeosporioides and Lasiodiplodia theobromae. The aim of this study was to evaluate the sensitivity of propagules of these pathogens to hydrothermal and UV-C treatments. Conidia suspensions and mycelial discs of each pathogen were subjected to treatments of hot water at 50, 55 and 58 ºC for 15 s and 30 s and UV-C radiation at doses of 0.330 kJ m-2, 0.660 kJ m-2 and 1.320 kJ m-2. After treatment and incubation for 72 and 48 h, we assessed the number of colony formation units (CFUs) and the mycelial growth of pathogens, respectively. Treatments showed distinct efficiency among propagules and pathogens. The control of CFUs and mycelial growth of C. gloeosporioides and L. theobromae was greater than 88% with water heated to 55 or 58 ºC, independent of treatment time. For the same pathogens, a higher dose of radiation, 1.320 kJ m-2, controlled over 96% of the CFUs. However, control of the mycelial growth of these pathogens with UV-C radiation was lower when compared to the use of water heated to 55 or 58 ºC. The control CFUs of A. alternata, M. roridum and F. pallidoroseum was higher with treatments of water heated to 55 ºC for 30 s, 58 ºC for 15 s and 30 s and with radiation doses of 0.660 kJ m-2 and 1.320 kJ m-2. The control of mycelial growth of A. alternata and M. roridum was lower with the radiation doses and temperature of 50 ºC when compared to the other treatments. As regards the reduction in the mycelial growth of F. pallidoroseum, treatments at 58 ºC or the doses of 0.660 and 1.320 kJ m-2 were more efficient and reached control of 88%. Water heated to 58 ºC for 15 s controlled the CFUs and the mycelial growth of the tested pathogens.
Cucumis melo; Mangifera indica; postharvest diseases; physical treatments
