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Title: Leaf application of a sprayable bioplastic-based formulation of biocontrol Aspergillus flavus strains for reduction of aflatoxins in corn

item ACCINELLI, CESARE - University Of Bologna
item Abbas, Hamed
item VICARI, ALBERTO - University Of Bologna
item SHIER, WAYNE - University Of Minnesota

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2015
Publication Date: 6/23/2016
Publication URL:
Citation: Accinelli, C., Abbas, H.K., Vicari, A., Shier, W.T. 2016. Leaf application of a sprayable bioplastic-based formulation of biocontrol Aspergillus flavus strains for reduction of aflatoxins in corn. Pest Management Science. 72(8):1521–1528. doi:10.1002/ps.4180.

Interpretive Summary: Mold called Aspergillus flavus produces aflatoxins which is a cancer causing chemical that contaminates corn. This is a major food safety concern. Isolates of an A. flavus that do not produce aflatoxins are used to control this cancer causing toxin. This study was used to determine the best delivery method for the non-toxigenic A. flavus strains (i.e., strains that do not produce toxins), which reduce toxin production by competing with the toxin-producing fungi. A sprayable formulation of bioplastic (starch -based material) granules decreased aflatoxins in corn more the previous method which used grain and also is more economical. This study provides a valuable advance and cost effective 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: Applying non-aflatoxin-producing Aspergillus flavus isolates to the soil has been shown to be effective in reducing aflatoxin contamination of harvested crops, including peanuts, cotton, and corn. Biocontrol isolates are commonly formulated as inoculated cereal grains applied to soil, where they act to reduce the percent aflatoxigenicity of A. flavus in the soil reservoir. Significant carryover to subsequent years can be demonstrated, but the usual practice is to apply biocontrol formulations annually. The long-range goal of this research program is to develop a biocontrol system that applies the minimum product only in years when long range weather/climate forecasts predict heat and/or drought during the kernel-filling period. We report here progress toward that goal using a novel sprayable formulation consisting of a partially gelatinized starch-based bioplastic dispersion embedded with spores of biocontrol A. flavus strains, which is applied to the leaf surfaces of corn plants. The formulation was shown to be adherent, resulting in colonization of leaf surfaces with the biocontrol strain of A. flavus, and to reduce aflatoxin contamination of harvested kernels up to 80% in Northern Italy, and 89% in the Mississippi Delta. The percent aflatoxigenicity of A. flavus in the soil reservoir under leaf-treated corn was not significantly changed, indicating that it is not necessary to treat the soil reservoir in order to achieve effective biocontrol of aflatoxin contamination in kernel corn. This observation was true even when the soil was amended with additional A. flavus, as a model of changes to the soil reservoir that occur in no-till agriculture. Additional studies are needed to optimize biocontrol of aflatoxin with sprayable formulations.