Poster # 110

Audrey Kalil ¹, Edson Ncube ¹, John Teixeira ¹, Taheni Gargouri-Jbir ¹, Dimitri Fonseka ¹, and Andrew Friskop ²
1. North Dakota State University, Williston Research Extension Center, Williston, North Dakota
2. North Dakota State University, Department of Plant Pathology, Fargo, North Dakota
Corresponding Author: Audrey Kalil, audrey.kalil@ndsu.edu

Edson Ncube

Fusarium graminearum causes Fusarium Head Blight (FHB) in durum wheat (Triticum durum Desf.), resulting in yield loss, low test weight and deoxynivalenol (DON) contamination. FHB is largely managed through the selection of varieties with increased resistance and fungicides. The goal of this study was to evaluate the efficacy of fungicides in single and sequential applications to manage FHB and DON in a susceptible (S) and a moderately susceptible (MS) cultivar. Field experiments were conducted under overhead irrigation to increase disease pressure, and set up in a randomized complete block design in 1.5 x 5.5 m plots, with four replications. Six field experiments were conducted from 2017-2022. The five fungicides treatments: Sphaerex (Met+Pro), Miravis Ace (Pro+Pyd), Miravis Ace followed by Tebuconazole (Pro+Pyd fb Teb), Prosaro (Pro+Teb) and Caramba (Met) were applied at different stages of crop development: half-head (Feekes 10.3), flowering (10.5.1), post flowering (4-6 days post 10.5.1), and both flowering and post-flowering (10.5.1 fb 4-6 days post-10.5.1) for a total of 8 fungicide x application timing treatments. The crop was assessed for visual FHB symptoms expressed as FHB index at soft dough, and yield and DON post-harvest. Fungicides significantly reduced FHB, reduced DON and protected yield in the experiments. Six fungicide treatments significantly protected durum yield. The sequential treatment of Prop+Pyd fb Teb provided the greatest amount of DON and FHB reduction, while having the highest yield. The MS cultivar exhibited a reduced FHB index and higher yield than the S cultivar. However, there was no significant difference in DON (P = 0.1811). Therefore, the integration of genetic resistance and proper timing of an effective fungicide application is an important strategy in the management of FHB. As new durum cultivars are released, it is essential to update existing and new fungicide performance data to convey messaging on efficacy and agronomic response, especially in growing regions that have sporadic FHB epidemics.