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Mycoflora of Pecans Treated with Heat, Low Temperatures, or Methyl Bromide for Control of the Pecan Weevil. John M. Wells, Plant Pathologist, Southeastern Fruit and Tree Nut Research Station, Agricultural Research Service, U.S. Department of Agriculture, Byron, Georgia 31008; Jerry A. Payne, Entomologist, Southeastern Fruit and Tree Nut Research Station, Agricultural Research Service, U.S. Department of Agriculture, Byron, Georgia 31008. Phytopathology 65:1393-1395. Accepted for publication 25 June 1975. DOI: 10.1094/Phyto-65-1393.

Fungus infection of weevil-damaged pecan kernels was reduced to percentages of 8.0 to 15.3% by hot water dips at 60 C for 10 and 15 minutes, or at 77 C for 3 minutes, and by steam treatments for 3 minutes, compared with infection of 81.6% in the controls. Average infection on pecans stored at 6 C was reduced to 56.3%, but was not affected by storage at 0 or at 6 C. Methyl bromide fumigation reduced infection on pecans treated at 1.6 and 3.3 kg/100 m3, but not at 0.8 kg/100 m3. Genera of fungi isolated and identified from untreated weevil-damaged kernels were Penicillium, Alternaria, Pestalotia, Monochaeta, Cladosporium, Fusarium, Phoma, and Aspergillus. Penicillium was the most common genus in heat-treated or fumigated pecans. Chloroform extracts of 28 of 92 representative Penicillium isolates, and one of 10 Aspergillus isolates were toxic to 1-day-old cockerels.

Additional keywords: mycotoxins, postharvest treatments.