Submitted to: APS Annual Meeting
Publication Type: Proceedings
Publication Acceptance Date: 4/5/2011
Publication Date: 6/1/2011
Citation: Jaime, R., Cotty, P.J. 2011. Community structure of Aspergillus flavus and persistence of the atoxigenic strain A flavus AF36 in applied fields. Proceedings of American Phytopathological Society Annual Meeting, August 4-8, 2011, Honolulu, HI. 101:S80. Interpretive Summary:
Technical Abstract: Aflatoxins are toxic and carcinogenic metabolites produced by several fungi in Aspergillus Section Flavi that frequently contaminate crops. Aflatoxins impact the value of crops. The use of atoxigenic strains of A. flavus to displace aflatoxin producers is a proven method to reduce aflatoxin contamination. Previous work indicated applications benefit both treated and subsequent crops. The current study sought to determine factors that influence persistence of AF36 and reestablishment of the highly toxigenic S strain of A. flavus. Results indicate significant differences between treated areas for both persistence of AF36 and development of the S strain. The percent of the A. flavus community composed of AF36 two years after application was higher in Mohawk Valley (> 70%) than in the Yuma Valley (50%), while S strain incidence was higher in the Yuma Valley (> 40%) than in the Mohawk Valley (20%). Regression analyses indicate that the Percent AF36 significantly decreased, while the Percent S significantly increased in the Yuma Valley. There was no significant change in either the Percent AF36 or the Percent S in the Mohawk Valley. Crop rotation significantly affects the structure of A. flavus communities. Cotton and lettuce production resulted in higher AF36 retention and reduced incidence of the S strain. The results suggest growing season, area, and crop rotation all influence the fungal community structure and long-term influences of the atoxigenic strain treatments.