ARS | Publication request: ASSESSING THE COLONIZATION POTENTIAL OF ASPERGILLUS FLAVUS STRAINS ON CORN UNDER FIELD CONDITIONS USING A PIN BAR INOCULATION TECHNIQUE

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 18, 2006
Publication Date: June 15, 2006
Citation: Abbas, H.K., Zablotowicz, R.M., Bruns, H.A. 2006. Assessing the colonization potential of aspergillus flavus strains on corn under field conditions using a pin bar inoculation technique. Phytopathology, 96:S2.

Technical Abstract: This study was conducted to assess the colonization potential of Aspergillus flavus strains as biological control agents to reduce aflatoxin contamination. Corn ears were inoculated at growth stage R4 with various A. flavus strains using a pin-bar inoculation technique in 2004 and 2005. Non-aflatoxigenic strains K49 and CT3 and toxigenic strain F3W4 were compared against the carrier control (aqueous tween 20). Following inoculation 10 corn ears were sampled every 48 hours, visually assessed for infected kernels, and modeled using the Gompertz growth model or the best fitting regression. Aflatoxin concentration was determined by HPLC at day 12 in 2004 and 2005. In both years the non-aflatoxigenic strain K49 demonstrated superior colonization to strain CT3. Strain F3W4 exhibited similar colonization to K49 in 2004, but reduced colonization in 2005. The Gompertz model characterized kernel colonization for all inoculated treatments in both years of study (r2 greater than or equal to 0.954). Considering both years of the study total aflatoxin concentration in the infected kernels was 35,000 ppb in F3W4 inoculated ears, 6,500 ppb in the carrier control, and less than 200 ppb in corn inoculated with non-aflatoxigenic strains CT3 and K49 12 days after inoculation. This data indicates that this technique can be used to elucidate colonization potential of non-toxigenic A. flavus in corn in relation to biological control of aflatoxin production.