VIEW ARTICLE

Combination Heat and 2,6-Dichloro-4-Nitroaniline Treatments for Control of Rhizopus and Brown Rot of Peaches, Plums, and Nectarines. John M. Wells, Plant Pathologist, Market Quality Research Division, ARS, USDA, 2021 South Peach Avenue, Fresno, California 93727; John M. Harvey, Investigations Leader, Market Quality Research Division, ARS, USDA, 2021 South Peach Avenue, Fresno, California 93727. Phytopathology 60:116-120. Accepted for publication 15 August 1969. DOI: 10.1094/Phyto-60-116.

Combined hot water and 2,6-dichloro-4-nitroani-line (DCNA) treatments of peaches, plums, and nectarines were more effective in the control of postharvest decays than either hot water or DCNA alone. Naturally-occurring decay was reduced from a mean of 65% in untreated peaches and nectarines to 7.8% in lots immersed for 1.5 min in water at 51.5ºC with 225 ppm DCNA. DCNA residues on fruit treated for 1.5 min in hot water with 225 ppm DCNA were equivalent to residues from treatments with 900 ppm DCNA in unheated water. Lesion diam on fruit inoculated with Rhizopus or Monilinia, and treated with hot water, decreased linearly as exposure time increased from 0.5 to 3 min. Regression coefficients of lesion diam on exposure times increased with increasing water temperatures. When 225 or 450 ppm DCNA was added to the hot water, equivalent inhibition of lesion development was possible with treatments of half the exposure times necessary with hot water alone.