Authors: Edson Ncube 1, Audrey Kalil 2, John Teixeira 1, Tyler Tjelde 1, and Andrew Friskop 3
1. North Dakota State University, Williston Research Extension Center, Williston, ND 58801
2. Horizon Resources Cooperative, Williston, ND 58801
3. North Dakota State University, Department of Plant Pathology, Fargo, ND 58108
Corresponding Author: Edson Ncube, edson.ncube@ndsu.edu
Presenting Author: Edson Ncube
Abstract
Durum wheat (Triticum durum Desf.) production in western North Dakota can be severely impacted by Fusarium Head Blight (FHB) due to lack of host resistance. Episodic infections and environmental conditions that are not always conducive for disease make it difficult to justify fungicide applications as an annual input. The goal of this study was to evaluate the effect of timed single and sequential fungicide applications on FHB index, yield, test weight (TW), and protein on an FHB-susceptible durum variety. Trials were conducted from 2022 to 2024 under overhead irrigation and set up in a randomized complete block design in 75 ft2 plots with five replications. Fungicide treatments evaluated included non-treated check, Prosaro® (prothioconazole + tebuconazole), Miravis Ace® (pydiflumetofen + propiconazole), Prosaro Pro® (prothioconazole + tebuconazole + fluopyram), Sphaerex® (prothioconazole + metconazole), and a Syngenta confidential product. Fungicide timing included single applications at early flowering (FKS 10.5.1), 4-6 days after FKS 10.5.1, or sequential applications at FKS 10.5.1 followed by an additional application 4-6 days later. Durum was assessed for visual FHB symptoms at soft dough while yield, TW, and protein data were collected post-harvest. Data were analyzed using the PROC GLIMMIX procedure in SAS, with fungicide and year as fixed effects, and replicate as a random effect. Results showed that all fungicides protected yield and TW in 2022 and 2024. Levels of FHB varied across the three study years; however, it was consistently negatively correlated with yield. In 2022, the highest yield was in the treatments which received sequential fungicide applications, which were also those that had significantly reduced FHB index. In that year, single fungicide applications did not reduce FHB index compared to the untreated check. The sequential applications as well as single applications of Prosaro Pro®, Miravis Ace® and Sphaerex® (FKS 10.5.1) suppressed FHB in 2023 while all fungicide treatments suppressed FHB in 2024. The delayed Sphaerex application timing (4-6 days post FKS 10.5.1) did not perform as well as the FKS 10.5.1 in FHB suppression in 2024 and yield in both 2022 and 2024. Grain protein levels showed no response to fungicides. This study suggests that under typical environmental conditions a single application timed at FKS 10.5.1 is sufficient to manage Fusarium Head Blight in western North Dakota.