An industry perspective on the use of “atoxigenic” strains of Aspergillus flavus as biological control agents and the significance of cyclopiazonic acid

Abstract

Several nonaflatoxigenic strains of Aspergillus flavus have been registered in the United States to reduce aflatoxin accumulation in maize and other crops, but there may be unintended negative consequences if these strains produce cyclopiazonic acid (CPA). AF36, a nonaflatoxigenic, CPA-producing strain has been shown to produce CPA in treated maize and peanuts. Alternative strains, including Afla-Guard^® brand biocontrol agent and K49, do not produce CPA and can reduce both aflatoxin and CPA in treated crops. Chronic toxicity of CPA has not been studied, and recent animal studies show significant harmful effects from short-term exposure to CPA at low doses. Grower and industry confidence in this approach must be preserved through transparency.

Keywords::

• aflatoxin
• mycotoxins
• competitive exclusion
• Afla-Guard^®
• AF36
• K49

Acknowledgements

The authors gratefully acknowledge the advice and assistance received from Drs. Tim Pastoor, John L. Richard, Susan Hunter Youngren, Robert Zablotowicz, Ms. Jacqueline Haley, and Jeff Stabnau during the preparation of this review article.

Declaration of interest

The authors are employees of Syngenta Crop Protection, LLC, which manufactures and markets Afla-Guard^® brand biocontrol agent. Afla-Guard^® is a registered trademark of a Syngenta Group Company.