Poster

Esmeralda Lagos ¹, Amina Kwiya ¹, Isaack Kikway ¹ and Pierce A. Paul ^1*
1. The Ohio State University, Wooster, OH 44691
Corresponding Author: Pierce A. Paul, Email: paul.661@osu.edu

Lagos, Esmeralda

lagos.11@osu.edu

Fusarium head blight (FHB) is an economically important wheat disease that reduces grain yield and quality and contaminates grain with mycotoxins such as deoxynivalenol (DON). Multiple fungicides are available for FHB and DON management, but there efficacy and costs vary by product, application timing, and number of applications. A web-based tool was developed to determine whether a fungicide application is warranted based on FHB risk as influenced by cultivar resistance and weather conditions. However, this tool has never been formally evaluated as a guide for choosing among fungicides or determining whether multiple applications are warranted. In this study, fungicide programs consisting of single and sequential applications of fungicides Miravis Ace (MIR), Prosaro (PRO), Sphaerex (SPH), A23751C (A23), Prosaro Pro (PRP), and tebuconazole (TEB) were evaluated under different FHB risk scenarios (consistently high-risk and high-to-moderate-risk from early to late anthesis) generated by planting moderately resistant (MR), moderately susceptible (MS), and susceptible (S) cultivars at two Ohio locations. Under both risk scenarios, single applications consisted of TEB, MIR, PRP, SPH, A23, or PRO at anthesis alone, whereas sequential applications consisted of MIR at anthesis, followed by TEB, PRP, SPH, A23, or PRO 3-4 days after anthesis under the high-risk scenario, or TEB, PRP, SPH, A23, or PRO at anthesis followed by TEB 3-4 days later under the moderate-to-high risk scenario. Untreated checks served as references for comparison and to evaluate efficacy in terms of percent control. All fungicide programs significantly reduced FHB index (IND) relative to the untreated check, with sequential-application programs consistently outperforming single-application programs, resulting in lower mean IND and greater percent control. Under the consistently high-risk scenario, sequential fungicide programs reduced IND by 50-81%, 81-91%, and 76-85% in S, MS, and MR cultivars, respectively. Single-application programs reduced IND by 23-72%, 48-77%, and 25-61% in S, MS, and MR cultivars, respectively. Under the moderate-to-high-risk scenario, the sequential application programs reduced IND by 84-95% on MR cultivars, 71-89% on MS cultivars, and 57-73% on S cultivars. The corresponding efficacy of single-application programs under moderate-to-high FHB risk ranged from 73-94%, 15-96%, and 33-89% control of IND on MR, MS, and S cultivars, respectively. Additional analyses will be conducted to evaluate efficacy against DON, and the entire study will be repeated across locations and growing seasons to further assess the efficacy and economic benefit of the tested fungicide programs under a wider range of FHB risk scenarios.

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