Integration of ultraviolet (UV-C) light with yeast treatment for control of postharvest storage rots of fruits and vegetables

Applications of low doses of ultraviolet light-C (254 nn, W-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 held infections and artificial inoculations. W-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-(butylcarbomoyl)-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 W-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%; W-C + D. hansenii, 12%; and benomyl alone (12%). Because the efficacy of W-C + D. hansenii was comparable to that of the postharvest fungicide used alone, it is indicated that an integration of W-C with the yeast treatment can be as effective as commercial postharvest fungicide treatment in reducing storage rots. Thus, integrated treatment with W-C and the biocontrol agent (yeast) has potential as an alternative means of postharvest disease control. (C) 1997 Academic Press.