Weather-Related Incidence of Aflatoxin Contamination in Late-Harvested Pecans. John M. Wells, Research Plant Pathologist, Southeastern Fruit and Tree Nut Research Laboratory, USDA, ARS, Byron, GA 31008. Jerry A. Payne, Research Entomologist, Southeastern Fruit and Tree Nut Research Laboratory, USDA, ARS, Byron, GA 31008, and Leonard Stoloff, Bureau of Foods, Food and Drug Administration, Washington, DC 20204. Plant Dis. 67:751-753. Accepted for publication 2 December 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1983. DOI: 10.1094/PD-67-751.

In surveys of pecan nuts in metropolitan market channels, 4.6% of samples were contaminated by aflatoxins from 1969 through 1980. In a related sampling of orchard pecans, aflatoxin contamination was found in weevil-damaged samples harvested late in the 1974–1975 season. Incidence in subsequent years has been negligible to nil. Weather records indicate that monthly average temperatures for December through February of each season since 1974–1975 have been below 8.7 C, compared with a normal temperature of 11.2 C. The limiting temperature of aflatoxin production on fresh pecans was determined to be 10 ± 1 C. Thus, monthly average temperatures during the later pecan season in the southeastern United States may be a significant factor in the incidence of aflatoxin contamination.