Poster # 106 View Poster

Gabriel de Moraes Chitolina and Carl A. Bradley
1. University of Kentucky, Department of Plant Pathology, Princeton, KY 42445
Corresponding Author: Carl A. Bradley, carl.bradley@uky.edu

de Moraes Chitolina, Gabriel

gabriel.chitolina@uky.edu

Fusarium head blight (FHB), caused by Fusarium graminearum, is a major disease affecting yield and quality of winter barley (Hordeum vulgare) grown in Kentucky. Field trials were conducted in Kentucky between 2020 and 2025 to evaluate the effects of fungicides on 2-row and 6-row winter barley cultivars for protection against deoxynivalenol (DON) contamination of harvested grain and for impact on yield. Integrated Management Trials (IMT) assessed fungicide products, application timing, and cultivars (‘Calypso’ and ‘Violetta’ for 2-row barley and ‘Secretariat’ and ‘Thoroughbred’ for 6-row barley), while Uniform Fungicide Trials (UFT) focused solely on fungicide products and application timing. Fungicide treatments included Prosaro®, Prosaro Pro, Miravis® Ace, Sphaerex®, Caramba®, Quadris®, and a tebuconazole fungicide, applied as single applications at Feekes growth stages 10, 10.3, or 10.5, single delayed applications 3–7 days after Feekes 10.5, or sequential applications after Feekes 10.5. Grain yield (kg/ha) at harvest and DON concentration (µg/g) in harvested grain were measured. Each trial was analyzed separately in SAS using PROC GLIMMIX. Fungicide treatment was a fixed effect, and year and replicate (nested within year) as random effects. In 2-row IMTs, fungicide and cultivar significantly affected DON and yield. Results from IMTs showed Miravis Ace produced the highest yield (5,423 kg/ha), while delayed Sphaerex 3 -7 days after Feekes 10.5 resulted in the lowest DON (1.05 µg/g). The cultivar ‘Calypso’ achieved the highest yield (5,219 kg/ha), where ‘Violetta’ had the lowest DON (1.40 µg/g). In 2-row UFTs, fungicide significantly affected DON but not yield. Sequential applications of Miravis Ace followed by Sphaerex, or delayed applications of Prosaro Pro or Sphaerex were most effective at reducing DON (0.97-1.08 µg/g), with Miravis Ace followed by tebuconazole attaining the highest yield (4,731 kg/ha). In 6-row IMTs, fungicide significantly affected DON but not yield, while cultivar significantly affected both yield and DON. IMT trials showed ‘Thoroughbred’ had the highest yield (5,727 kg/ha) and lowest DON (1.71 µg/g), and a single application of Caramba at Feekes 10.5 resulted in the lowest DON (1.90 µg/g). In the 6-row UFTs, fungicide significantly affected DON but not yield. Sequential applications of Miravis Ace followed by Prosaro or Caramba, and delayed Miravis Ace 3–7 days after Feekes 10.5, were most effective at reducing DON (1.22-1.38 µg/g), while maintaining high yields (4,616-5,257 kg/ha). This study provides insights into FHB management in Kentucky and can inform future integrated disease management practices for winter barley growers.

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