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Postharvest Pathology and Mycotoxins

Sour Rot of Peaches Caused by Monilia implicata and Geotrichum candidum. John M. Wells, Plant Pathologist, U. S. Department of Agriculture, Agricultural Research Service, Southeastern Fruit and Tree Nut Research Station, P. O. Box 87, Byron, GA 31008; Phytopathology 67:404-408. Accepted for publication 24 September 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-404.

Losses due to sour rot caused by Monilia implicata and Geotrichum candidum were consistently greater on peaches experimentally waxed with 2,6-dichloro-4-nitroaniline (DCNA) and benomyl after hydrocooling in nonchlorinated water than on unwaxed peaches similarly hydrocooled. On peaches from a commercial packing shed with poor sanitation and grading practices, sour rot developed in three out of seven tests and affected 3.8 to 48.7% of the fruit. On peaches from a shed with good sanitation practices, sour rot developed in two of seven tests and affected less than 1% of the fruit. Frequency of isolation of organisms from infected fruit was 54.8% for M. implicata and 13.6% for G. candidum. On inoculated peaches, growth (lesion diameter) of M. implicata at 21 C was nearly three times as great as growth of G. candidum, but on artificial media it was significantly less than that of G. candidum. Concentrations of 1 or 10 μg/ml DCNA or benomyl (residues normally found on waxed peaches) did not affect, or inhibited only slightly, the growth of both organisms on artificial medium