Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2009
Publication Date: 4/10/2010
Citation: Dorner, J.W. 2010. Efficacy of a biopesticide for control of aflatoxins in corn. Journal of Food Protection. 73:495-499.
Interpretive Summary: Aflatoxin contamination of crops compromises the safety of food and feed supplies and causes significant economic losses each year. Aflatoxin contamination can occur when crops are infected with aflatoxin-producing strains of Aspergillus flavus and A. parasiticus, molds that are relatively abundant in agricultural soils. Afla-guard is a product that has been developed in recent years by ARS for biological control of aflatoxin contamination. Its mode of action is to establish a dominant soil population of a nontoxigenic strain of A. flavus that displaces toxigenic strains during crop infection. Afla-guard has been approved by the U. S. Environmental Protection Agency (EPA) for use on peanuts and is now being used commercially in that crop. The purpose of this two-year study was to gather data in large-scale field studies to determine the efficacy of afla-guard for control of aflatoxin in corn. Afla-guard was applied at rates of 10 or 20 pounds per acre to commercial fields of corn in 2007 and 2008 in Texas. Results showed that each treatment rate produced significant reductions in aflatoxin in both years with no difference being seen between the two rates. When data for both treatment rates were combined, aflatoxin reductions averaged 85 and 88% for the respective years. As a result of this demonstration of efficacy, the EPA has approved the use of afla-guard for control of aflatoxin contamination in corn.
Technical Abstract: A two-year study was carried out to determine the efficacy of an aflatoxin biocontrol product in reducing aflatoxin contamination in corn. The product, afla-guard7, delivers a nontoxigenic strain of Aspergillus flavus to the field where it competes with naturally-occurring toxigenic strains of the fungus. Afla-guard was applied to entire fields in two areas of Texas at either 10 or 20 lb/acre. Specific non-treated fields in close proximity to treated fields were designated as controls. Samples of corn were collected at harvest and analyzed for aflatoxins and density of toxigenic and nontoxigenic isolates of A. flavus. Aflatoxin concentrations were generally quite low in 2007, but the mean concentration in treated samples (0.5 ppb) was reduced by 85% compared with controls (3.4 ppb). In 2008, samples from treated and control fields averaged 1.5 and 12.4 ppb, respectively, an 88% reduction. There were no significant differences between the two afla-guard application rates. In conjunction with the reductions in aflatoxin contamination, treatments produced significant reductions in the incidence of toxigenic isolates of A. flavus in corn.