Project Number: 6402-42000-005-00
Start Date: Dec 31, 2011
End Date: Dec 30, 2016
Maize (corn) production in the United States is valued at $65 billion annually. Infection of corn by some strains of Aspergillus (A.) flavus, and subsequent contamination with the mycotoxin aflatoxin, results in costs of $923 million (UN Food and Agriculture Organization) and illnesses, including cancer or death in livestock and humans. Fungicides, altered agronomic practices and breeding efforts, including the use of transgenic Bt-corn have all been insufficient in mitigating aflatoxin contamination. Presently, the most effective approach to reduce aflatoxin contamination in corn is biological control, using non-aflatoxin-producing strains of A. flavus, as developed by USDA-ARS researchers. This technology is now commercially available as Afla-Guard®. Substantial progress has been made in the implementation of this product, but important research questions remain, which are addressed in this proposal: First, the post-release environmental fate of non-toxigenic strains of A. flavus must be evaluated. This is an essential environmental stewardship issue and may yield insight into A. flavus ecology and the plant disease cycle. Another objective includes experiments to evaluate mechanisms of biological control, including a model to explain why biocontrol strains are more effective at reducing aflatoxin contamination than predicted by simple competition. Finally, improvements in formulation and application methods of A. flavus biocontrol strains are needed for better, more consistent aflatoxin control. The commercialization of Afla-Guard® was important in the effort to exclude aflatoxin from food and feed. The basic and applied research in this proposal is essential to complete the implementation of the biocontrol strategy for reducing aflatoxin contamination of corn.