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Effect of Chemical and Biological Agents on the Incidence of Aspergillus flavus and Aflatoxin Contamination of Peanut Seed. A. C. Mixon, Research agronomist, Agricultural Research Service, USDA, University of Georgia, Coastal Plain Station, Tifton 31793; D. K. Bell(2), and D. M. Wilson(3). (2)(3)Associate professor and professor, Department of Plant Pathology, University of Georgia, Coastal Plain Station, Tifton 31793. Phytopathology 74:1440-1444. Accepted for publication 3 July 1984. 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, 1984. DOI: 10.1094/Phyto-74-1440.

Chemical and biological soil amendments were investigated for effects on seed colonization by fungi of the Aspergillus flavus group (A. flavus and A. parasiticus) and, in certain instances, on aflatoxin contamination of one or more genotypes of peanut (Arachis hypogaea). During 1976, 1977, 1981, and 1982, granular and/or liquid pesticide formulations and Trichoderma harzianum were applied either as soil amendments or as postharvest liquid applications to peanut pods. In 1981 and 1982, soil treatments also were applied to plots treated with surface applications of 0, 673, and 1,345 kg of gypsum per hectare. Peanut genotypes grown with chemicals applied to either the soil (both alone and in certain combinations) or to the pods of these genotypes varied in colonization of the seed by the A. flavus group of fungi. Gypsum applications reduced the percentage of seed colonized by these fungi. Applications of gypsum also enhanced the control of seed colonization in plots treated with T. harzianum, PCNB-fensulfothion, or CGA 64250, but treatment and genotype interactions were noted. No aflatoxin was detected in peanuts harvested from gypsum-treated plots, but it was occasionally found in peanuts from the non-gypsum treatments resulting in a highly significant treatment genotype interaction.

Additional keywords: biological toxins, pest resistance, seed contamination.