Preharvest Aflatoxin Contamination of Dent Corn in Indiana in 1983. John Tuite, Professor, Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907. Ronald Sensmeier, Chemist, Indiana State Chemist’s Office, Cindi Koh-Knox, Technician, Department of Botany and Plant Pathology, and Rodney Noel, Chemist, Indiana State Chemist’s Office, Purdue University, West Lafayette, IN 47907.. Plant Dis. 68:893-895. Accepted for publication 20 April 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-893.

A survey of 493 fields of dent corn from 67 Indiana counties in 1983 revealed that 17% of the shelled samples were positive for bright green-yellow fluorescence (BGYF). Twelve percent of the ear samples were positive for BGYF. BGYF samples, whether detected on the ear or when shelled or both, equaled 19.3% of the samples. Of the BGYF samples, 41.7% were positive for aflatoxin as determined by the Holaday-Landsden minicolumn (MC) method. Most (94.7%) of the MC samples positive for aflatoxin were also positive as determined by the Official Association of Official Analytical Chemists thin-layer chromatography method. Overall 7.3% of the samples were positive for aflatoxin. The average concentration of aflatoxin B₁ was 65.7 and 79.9 ppb total aflatoxin. Almost three-fourths of the positive samples had more than 20 ppb, and of those with more than 20 ppb, one-fourth had more than 100 ppb. The highest amount of total aflatoxin was 471 ppb. Three of 50 samples negative for BGYF when shelled contained aflatoxin but at 20 ppb or less. A survey of 118 elevator dent corn samples during November and December 1983 indicated a slightly lower incidence of aflatoxin (6.7%), a lower range (20–97 ppb) than for preharvest corn. There was a greater incidence of aflatoxin in the western counties. Most counties suffered from high temperatures and drought but western counties in the west central and west southern areas had more severe conditions.

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