Elicitation of Resistance Against Pathogens in Citrus Fruits by Combined UV Illumination and Heat Treatments

Combined heat and UV treatments reduced decay and maintained quality of kumquat and 'Washington Navel' orange better than either treatment alone. Heat treatment followed by UV-C illumination was the most effective combination in controlling postharvest decay with hot water dip or hot air curing reducing the damage induced by subsequent UV-C treatment. If UV treatment preceded heat treatment, the elicitation of phytoalexins was inhibited. UV-C irradiation is considered a potential additional tool in the decay control arsenal of citrus fruits, although UV by itself cannot match the high efficiency of decay control achieved by current fungicides.