<UL><LI>Extend development of atoxigenic strain technology and characterization of the epidemiology of cottonseed contamination.<LI> Improve atoxigenic strain formulations and recommendations for on-farm use of atoxigenic strains. <LI>Identify factors influencing over-wintering of atoxigenic strains and agronomic practices that optimize atoxigenic strain performance including sporulation, dispersal, crop colonization, and over-wintering. Increase understanding of the biology and epidemiology of the highly toxigenic S strain.
Approach: Models will be developed that predict aflatoxin contamination of cotton and S strain incidence in agricultural fields from environmental and agronomic parameters. To identify factors favoring S strain development in commercial fields, communities will be monitored in several regions with varying initial incidences of the S strain. Factors identified as favoring the S strain will be tested in vitro. Incidence, distribution, and behavior of S strain sclerotia will be evaluated in commercial fields to assess roles and S strain life cycles. Dynamics of fungal community compositions as related to atoxigenic strains and the S strain will be monitored during diverse crop rotations in Arizona, including production of winter and spring produce prior to cotton or corn. Sorghum grain will be incorporated into advanced formulations and evaluated in commercial fields as a potential less expensive, more efficacious alternative to wheat.