Impacts of the Midwest 2012 drought on aflatoxin contamination of maize
A. E. ROBERTSON (1), C. A. Bradley (2), C. Hurburgh (3), D. Jardine (4), R. Pruisner (5), K. Wise (6). (1) Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, U.S.A.; (2) Department of Crop Sciences, University of Illinois, Urbana, IL, U.S.A.; (3) Department of Agriculture and Biosystems Engineering, Iowa State University, Ames
Aflatoxin contamination of maize occurs when grain is infected by <i>Aspergillus flavus</i>, the causal organism of Aspergillus ear rot. This disease is favored by dry, hot conditions, followed by some moisture after black layer. Aflatoxin is a potent toxin and carcinogen that is regulated by the Food and Drug Administration (FDA) who have set an action level of 20 ppb. During the 2012 growing season, much of the Corn Belt experienced severe to extreme drought conditions and concerns regarding aflatoxin contamination were high. The FDA approved temporary blending policies for aflatoxin in several states so that corn up to 500 ppb of aflatoxin could be blended for use in appropriate animal feed. The prevalence of Aspergillus ear rot was low in many states. In Iowa, mean ear rot severity was less than 2 percent in field trials. Aflatoxin levels detected in grain at harvest throughout the Midwest also were low. In surveys conducted by the Iowa and Illinois Departments of Agriculture and Land Stewardship, 6 and 20 percent of grain samples collected from local elevators in each county of Iowa and Illinois, respectively, contained >20ppb aflatoxin. The state average for Iowa was 5.5 ppb, below 21 ppb that occurred during the 1983 drought. Reports of aflatoxin-contaminated feed surfaced in early 2013 indicating incorrect sample handling may have played a role in the low levels detected at harvest.
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