Development and commercial use of afla-Guard^®, an aflatoxin biocontrol agent

Abstract

A biopesticide, afla-guard^®, has been developed for controlling aflatoxin contamination in peanuts. This product provides the means of introducing a competitive, non-aflatoxigenic strain ofAspergillus flavus into soils where peanuts are being grown. The introduced strain competitively excludes toxigenic strains naturally present from invading developing peanuts. The biocontrol technology was made commercially available in 2004 by Circle One Global, Inc., upon receiving U.S. Environmental Protection Agency section 3 registration of afla-guard^® as a biopesticide. The product was applied to approximately 2000 ha of peanuts in Georgia and Alabama during the 2004 crop year. Application of afla-guard^® changed the composition ofA. flavus soil populations from an average 71.1% toxigenic strains in untreated fields to only 4.0% in treated soils. Analyses of farmer's stock peanuts being delivered at seven different locations showed a consistent reduction in aflatoxin contamination in peanuts from fields treated with afla-guard^®. Over all locations, aflatoxin averaged 78.9 ng/g in untreated peanuts compared with 11.7 ng/g in treated peanuts, an 85.2% reduction. Peanuts from treated and untreated fields were stored together in separate warehouse bins at two different locations. Aflatoxin analyses at the Unadilla, GA location showed that 48.4% of shelled edible lots from untreated fields contained unacceptable levels of aflatoxin (>15 ng/g). At the Dawson, GA location, 15.8% of shelled lots from untreated fields contained >15 ng/g. At both locations, no shelled edible lots from treated fields contained >15 ng/g. Mean aflatoxin concentrations in edible peanuts from untreated and treated fields at Unadilla were 36.2 and 0.9 ng/g, respectively. At Dawson the respective means were 7.2 and 2.2 ng/g.