Poster

Ryan Hamilton ¹, Jillian Check ^1,2, Adam Byrne ^1,3, John Boyse ¹, William Widdicombe ¹, Jessica Scherer ⁴, Bryan Hansen ⁴, Christian Kapp ⁵, James DeDecker ⁵, Andrew Friskop ⁴, and Martin Chilvers ¹
1. Michigan State University, Department of Plant, Soil and Microbial Sciences, East Lansing, MI
2. Corteva Agriscience, Johnston, IA
3. FMC Corporation, Agricultural Solutions, Philadelphia, PA
4. North Dakota State University, Department of Plant Pathology, Microbiology, and Biotechnology, Fargo, ND
5. Michigan State University, Upper Peninsula Research and Extension Center (UPREC), Chatham, MI
Corresponding Author: Martin Chilvers, chilvers@msu.edu

Hamilton, Ryan

hamil486@msu.edu

Management of Fusarium head blight (FHB) in spring and winter malting barley requires balancing grain yield, deoxynivalenol (DON) contamination, and end-use quality. However, fungicide-mediated yield protection does not necessarily correspond with reduced DON contamination, and potential effects on malting quality must also be considered. Field trials conducted across seven site-years in Michigan (winter barley) and North Dakota (spring barley) from 2020 to 2022 evaluated 48 fungicide treatment programs relative to non-treated controls. Programs included single applications at Feekes growth stages 8–9 (targeting foliar diseases), Feekes 10–10.5 (heading), or 4–6 days after Feekes 10.5, as well as sequential applications. Grain yield, DON, kernel plumpness, thin fraction, protein, germinative energy, germinative capacity, water sensitivity, and Rapid Visco Analyzer units (RVU) were evaluated using site-year-specific statistical analyses. Significant yield differences occurred in five of 48 comparisons, exclusively in North Dakota during 2020. Of 26 fungicide treatment comparisons for DON, nine resulted in significant reductions and two in significant increases relative to non-treated controls. Two programs that included an early application at Feekes 8–9 (targeting fungal foliar disease) significantly increased both yield and DON, highlighting that yield protection does not necessarily indicate effective mycotoxin management. In Michigan during 2020, a single Miravis Ace application 4–6 days after Feekes 10.5 significantly reduced DON relative to the non-treated control (ratio = 0.49; adjusted P = 0.0037), whereas applications at heading did not significantly reduce DON. Eight additional significant DON reductions were identified in exploratory analyses of Michigan 2022 trials, although DON concentrations in non-treated controls were below 1.0 ppm. Fungicide treatments significantly protected kernel plumpness in 14 of 42 comparisons and decreased thin fraction in seven of 42, while significant responses in germinative energy and RVU were uncommon. Malting quality varied substantially among Michigan site-years. All treatment and control means met the ≥120 RVU screening threshold in 2020 and 2022, whereas none met this threshold in 2021, including both cultivars evaluated. These findings demonstrate that yield protection, DON mitigation, and malting quality are distinct management outcomes. Fungicide programs should therefore be selected according to their intended purpose, distinguishing early applications targeting foliar diseases from appropriately timed applications targeting FHB and DON contamination, while considering cultivar adaptation and environmental influences on malting suitability.

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