Fusarium graminearum is Fusarium head blight’s (FHB) or scab disease main causal agent. Apart from reducing yield and kernel quality, one of FHB’s critical impacts is accumulation of mycotoxins such as deoxynivalenol (DON). This study assessed the efficacies of newer fungicides on FHB and DON management under different application regimens. The fungicide application regimen comprised three schemes; a single application of Prosaro (6.5 fl oz/ac), Caramba (13.5 fl oz/ac), Miravis Ace (13.7 fl oz/ac), Prosaro Pro (10.3 fl oz/ac) and Sphaerex (7.3 fl oz/ac) at early anthesis (Feekes 10.5.1), a sequential application of two different products starting at Feekes 10.5.1 followed by an application at completion of flowering (Feekes 10.5.3), and a single application of Prosaro Pro, Sphaerex, and Miravis Ace at the completion of flowering. ‘CP3099A’, an awnless spring wheat variety was used as a model susceptible host. The study was set up as a randomized complete block design with four blocks and all experimental units were inoculated at boot stage with F. graminearum infected corn spawn at 42g m^-2. Data on FHB index, FDK and DON were analyzed using the generalized linear model with applicable functionalities. The sequential fungicide application and the Feekes 10.5.3 single application regimes had lower FHB index, FDK and DON accumulation relative to the widely used single applications. Miravis Ace applied at Feekes 10.5.1 followed by Prosaro Pro at Feekes 10.5.3 had the lowest FHB index, FDK and DON accumulation. No statistically significant differences in DON accumulation were observed among treated plots regardless of application regimen. However, plots subjected to sequential and late applications had distinctly lower DON than plots with a single fungicide application at Feekes 10.5.1. Although none of the samples analyzed in this study met the FDA restrictions of 1ppm for safe human consumption, results suggest that a sequential scheme is the most effective for managing FHB index, FDK, and DON accumulation. The single fungicide application scheme at Feekes 10.5.3 provided better FHB index and DON protection compared to single application at Feekes 10.5.1. These preliminary observations defy the current recommendation to apply fungicide at Feekes 10.5.1for effective FHB management. Perhaps, there is an association between application times and host genotype, disease pressure and environmental conditions.

ACKNOWLEDGEMENT AND DISCLAIMER

This is based upon work supported by the USDA Agreement No 59-0206-2-090. This is a cooperative project with the U.S. Wheat & Barley Scab Initiative. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the U.S. Department of Agriculture.