Influences of weather on aflatoxin-producing fungi and aflatoxin concentrations in crops
P. J. COTTY (1), A. Ortega-Beltran (2), R. Jaime (2). (1) USDA ARS, Tucson, AZ, U.S.A.; (2) University of Arizona, Tucson, AZ, U.S.A.
Aflatoxins are potent mycotoxins that reduce development, impair the immune system, and cause cancer and death. Several <i>Aspergillus</i> species produce aflatoxins during crop infection, which is greatly influenced by weather events including freezes, droughts, rainfall, and shifts in temperature. Weather also influences the average aflatoxin-producing potential of the fungi. Contamination occurs both during crop development and after crop maturation. Interactions of aflatoxin-producers with agronomic practices and weather events at specific crop stages determine the magnitude of contamination through effects on pests, crops, and timing of activities. Weather events that favor high contamination during crop development may suppress contamination after crop maturation either prior to harvest or during post-harvest handling and storage. Routine crop monitoring provides large sets of geographically referenced data useful in describing influences of weather on contamination across regions, states, and even continents. Knowledge of weather influences facilitates both better monitoring and improved cost-benefit ratios through weather-based adjustment of management strategies. Recent episodes of severe contamination on maize and cottonseed underscore the importance of weather influences and the need to adjust cropping cycles and management practices in order to avoid losses associated with aflatoxins.
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