Integration of Ultraviolet (UV-C) Light with Yeast Treatment for Control of Postharvest Storage Rots of Fruits and Vegetables

Abstract

Applications of low doses of ultraviolet light-C (254 nm, UV-C), UV-C in combination with a biocontrol agent, Debaryomyces hansenii, or postharvest fungicides were compared for their ability to reduce the incidences of brown rot caused by Monilinia fructicola of peach, green mold ( Penicillium digitatum ) of tangerine, and Rhizopus soft rot ( Rhizopus stolonifer ) of tomato and sweetpotato that resulted from both field infections and artificial inoculations. UV-C light alone reduced the incidence of storage rots of all produce. However, in general, application of the postharvest fungicide benomyl (Benlate 50 DF; methyl-1-(butyl-carbomoyl)-2-benzimidazole carbamate) or dichloran (Botran 75WP; 2,6-dichloro-4-nitroaniline) was more effective than UV-C treatment alone. When the produce were treated with D. hansenii 2 to 3 days after UV-C treatment, the reduction of storage rots was better than when UV-C was used alone. The percentage of brown rot infection of “Elberta” peaches 36 h after artificial inoculation were untreated control, 100%; UV-C alone, 55%; D. hansenii alone, 67%; UV-C + D. hansenii, 12%; and benomyl alone (12%). Because the efficacy of UV-C + D. hansenii was comparable to that of the postharvest fungicide used alone, it is indicated that an integration of UV-C with the yeast treatment can be as effective as commercial postharvest fungicide treatment in reducing storage rots. Thus, integrated treatment with UV-C and the biocontrol agent (yeast) has potential as an alternative means of postharvest disease control.