Fusarium head blight (FHB) continues to be one of most significant diseases affecting hard red spring wheat (HRSW) production in North Dakota. The implementation of integrated management practices such as the use of fungicides and host resistance, can drastically decrease yield and cause quality losses. However, as new fungicides and wheat varieties are released and disease risk fluctuates each growing season, the use of both management practices may not be necessary every year. The objective of this research was to evaluate fungicides and varietal resistance to suppress FHB and DON in HRSW in varying FHB risk dryland environments. From 2019 to 2021, seven integrated management field experiments were conducted at three locations in eastern North Dakota. The field experiments were conducted in a randomized complete block design, with a split plot arrangement. Two HRSW varieties, WB-Mayville (susceptible) and ND-VitPro (moderately resistant) served as the main plots and seven fungicide treatments including a non-treated control served as the sub-plots. Five single fungicide application treatments consisted of Prosaro (prothioconazole+tebuconazole), Caramba (metconazole), Sphaerex (metconazole+prothioconazole), Folicur (tebuconazole), and Miravis Ace (pydiflumetofen+propiconazole) and were applied at early anthesis (Feekes 10.5.1). One fungicide treatment of Sphaerex, was applied three to seven days after early anthesis. Individual plots were inoculated with Fusarium infected corn spawn at jointing (Feekes 6) to increase disease risk. DON, incidence, severity and Fusarium damaged kernel (FDK) data was used to create a DISK value. The DISK value was used to statistically categorize the seven location*years into four unique FHB management environments; high, moderate, low, and no risk. Additionally, yield and test weight data was collected to evaluate yield response from a fungicide application. In high and moderate environments, the moderately resistant variety significantly reduced DISK In the high environment, statistical differences were also observed among treatments. All fungicide treatments significantly reduced DON levels, except Folicur. In low FHB environments, Miravis Ace and both application timings of Sphaerex significantly reduced DON and had higher yield than the NTC. Additional analyses on the use of fungicides in varying FHB management environments will help refine decisions for hard red spring wheat producers. 

Acknowledgements

We would like to thank the North Dakota Wheat Commission for supporting this project.