Technical Abstract: Aflatoxins are highly toxic cancer causing Aspergillus metabolites that cause immune-system suppression, growth retardation, cancer and death in both humans and domestic animals. Aflatoxin-producing species have considerable intraspecific variability, and the species that causes most aflatoxin contamination of crops, Aspergillus flavus, varies widely in aflatoxin production with some strains producing no aflatoxins. Biocontrol strategies for reducing aflatoxin contamination have been developed that utilize strains of A. flavus that do not produce aflatoxins to competitively exclude aflatoxin producers. In commercial practice, these atoxigenic strains are applied during crop development on a fungal food source that fuels initial reproduction and dispersal of the biocontrol agent. Although applications alter the composition of A. flavus communities associated with crops and, as a result, reduce crop aflatoxin content, both crop infection by A. flavus and the quantity of A. flavus on the crop at harvest are no different in treated and untreated crops. Long-term influences of atoxigenic strain treatments have led to efforts to develop area-wide aflatoxin management programs. It is within such programs that the greatest potential for atoxigenic strain use may reside. However, for optimal benefits, improved methods for utilizing atoxigenic strains must be envisioned and developed. It is likely these will include methods that simultaneously utilize multiple strains.