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Heated Wax-Emulsions with Benomyl and 2,6-Dichloro-4-Nitroaniline for Control of Postharvest Decay of Peaches and Nectarines. John M. Wells, Plant Pathologist, Market Quality Research Division, ARS, USDA, 2021 South Peach Avenue, Fresno, California 93727, Present address: Market Quality Research Division, ARS, USDA, Plant Industry Station, Beltsville, Maryland 20705; Phytopathology 62:129-133. Accepted for publication 10 August 1971. DOI: 10.1094/Phyto-62-129.

Mean diameters of lesions on fruit inoculated with Monilinia fructicola or Rhizopus stolonifer and treated with heated (52 C) or unheated (24 C) dips or sprays for 10, 20, or 30 sec with 225, 450, or 900 µg/ml of 2, 6-dichloro-4-nitroaniline (DCNA) suspended in a wax emulsion were significantly smaller than those on fruit similarly treated with DCNA suspended in water. Similar wax-benomyl treatments at 10, 33, or 100 µg/ml were also more effective in reducing lesion diameters of Monilinia-inoculated fruit than were benomyl treatments alone. Heated DCNA treatments, whether as dips or sprays, and with or without wax, were more effective than unheated treatments. Heat improved the effectiveness of benomyl only as a dip, a 30-sec spray (without wax), or 10-sec wax spray. Mean per cent decay of noninoculated peaches and nectarines due to infections by Monilinia and Rhizopus was significantly less when treated for 10 sec with a heated wax spray containing 450 µg/ml DCNA and 100 µg/ml benomyl than when sprayed for 3 sec with the same wax-fungicide mixture unheated under commercial conditions.