The purpose of this work was to evaluate the effect of UV-C irradiation in vitro to control M. fructicola and R. stolonifer and the diseases caused by them in peach fruits. Mycelial growth was evaluated after exposure of the pathogens on PDA medium to different UV-C irradiation concentrations of 0, 0.26, 0.52, 1.04, 3.13, 5.22, 10.44, 15.66 and 31.32 kJ.m-2. The UV cabinet was equipped with four lamps with the fluency rate of 1.74 mW.cm-2. Peach fruits were treated with UV-C irradiation in a protective and curative way. In the protector treatment, fruits were exposed to 1.04 kJ.m-2 for 1 min. and were inoculated immediately and after 16, 24 and 40 hours. In the curative treatment, peach fruits were inoculated, incubated and irradiated with 0, 1.04, 5.22, 10.44, 15.66 and 31.32 kJ.m-2 UV-C concentrations. Disease incidence and severity of brown rot were evaluated. In vitro, only the concentrations applied during 1 and 10 min. of exposure reduced the mycelial growth of M. fructicola, while the application of UV-C for 10-15 minutes reduced the mycelial growth of R. stolonifer and the concentration applied for 30 minutes completely inhibited the mycelial growth of this pathogen. There was no effect caused by UV-C light in the protective control, or by UV-C light in the curative control of brown rot. The irradiation of fruits with UV-C was effective in the curative control of soft rot, and the best results were observed with an exposure time of 10 minutes.
Prunus persica; alternative control; postharvest disease
