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United States Department of Agriculture

Agricultural Research Service

Research Project: Biocontrol of Aflatoxin and Other Mycotoxins in Maize Using Non-toxigenic Strains of Aspergillus flavus

Location: Biological Control of Pests Research Unit

Title: Aflatoxin contamination of corn under different agro-environmental conditions and biocontrol applications

Authors
item Accinelli, Cesare -
item Abbas, Hamed
item Vicari, Alberto -
item Shier, Wayne Thomas -

Submitted to: Crop Protection Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2014
Publication Date: May 22, 2014
Citation: Accinelli, C., Abbas, H.K., Vicari, A., Shier, W. 2014. Aflatoxin contamination of corn under different agro-environmental conditions and biocontrol applications. Crop Protection Journal. 63:9-14.

Interpretive Summary: Contamination of food crops with toxins produced by the fungus Aspergillus flavus (aflatoxins, cyclopiazonic acid) is a major food safety concern, because aflatoxins are potent cancer-causing substances that commonly contaminate corn. A biological approach to reducing toxin production by toxigenic A. flavus contaminants is to treat crop plants and/or the soil with non-toxigenic A. flavus strains (i.e., strains that do not produce toxins), which reduce toxin production by competing with the toxin-producing fungi. To enhance the efficacy of non-toxigenic A. flavus strains, they were formulated with bioplastic granules by a new approach that gives improved effectiveness and tested for aflatoxin reduction in the field in two different geographical areas. This study provides a valuable advance in formulation technology for biological control A. flavus strains that should prove useful for researchers and for biotechnology companies that market biological control products.

Technical Abstract: Biological control of the fungus Aspergillus flavus has been shown to be effective in reducing aflatoxin contamination in corn. This study compared field application of a bioplastic-based formulation for delivering atoxigenic A. flavus isolates in Northern Italy and the Mississippi Delta. RESULTS: Due to an extremely hot and dry summer at the Italy site in 2012, aflatoxin contamination was approximately seven times higher than in 2011. In 2011 and 2012, application of bioplastic granules inoculated with the atoxigenic isolate A. flavus NRRL 30797 at 15 and 30 kg ha-1 resulted in a reduction of aflatoxin contamination by 67.2 ± 4.1% and 94.8 ± 5.3%, respectively. The higher application rate was also effective when soil abundance of A. flavus was artificially increased by applying contaminated corn residues. At the Mississippi site, summer 2012 was also hot and dry, with high levels of aflatoxin contamination. In fields planted with non-Bt or Bt hybrids, application of biocontrol granules inoculated with A. flavus NRRL 30797 or NRRL 21882 at 30 kg ha-1 reduced aflatoxin contamination to up to 89.6%. CONCLUSIONS: Field experiments on two continents showed that bioplastic-based A. flavus formulations markedly reduced aflatoxin contamination under different agro-environmental conditions and infestation intensities.

Last Modified: 10/30/2014
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