Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: May 14, 2012
Publication Date: N/A
Technical Abstract: Aflatoxin contamination is a perennial threat to corn production in the southern United States. Aspergillus flavus is the predominant species associated with aflatoxin production;however, not all strains produce the toxin. Two non-aflatoxigenic strains of A. flavus were evaluated during 2011 at five field sites in the Mississippi Delta. Afla-Guard, a commercially available formulation of non-toxigenic A. flavus (NRRL 21882), was tested at three application (V10, VT and R2) timings and at two application rates (11 and 22 kg/ha) alongside untreated control plots and other plots treated with strain K49 (NRRL 30797), a Mississippi-native biocontrol strain of A. flavus. Minimum and maximum air temperatures were above average with less precipitation than average at Stoneville, MS in June and July. Three of the five sites had = 5 ppb aflatoxin, so it was not possible to attribute any aflatoxin reduction to the biological control strain application. The remaining two sites, in contrast, were heavily contaminated with aflatoxin, with concentrations from individual plots between 30 to 540 ppb aflatoxin. Higher application rates (22 kg/ha) and early application (V10) were generally the most effective, and strain K49, applied at V10, resulted in the lowest contamination concentrations, but the differences were not statistically significant.