Poster # 119

Mitali Banik¹, Maurice Penner¹, David Overy ², Tom Witte ², Raja Khanal ² and Xiben Wang¹
1. Morden Research and Development Centre, Agriculture and Agri-Food Canada, Morden, MB, Canada
2. Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0C6, Canada
Corresponding Author: Xiben Wang, xiben.wang@agr.gc.ca

Wang, Xiben

xiben.wang@agr.gc.ca

Fusarium head blight (FHB) is a major disease of barley that causes significant grain yield and quality losses in Western Canada. The disease is caused by a complex of Fusarium species, with F. graminearum as the primary pathogen, while F. poae and F. sporotrichioides have become increasingly prevalent. Triazole fungicides are widely used to manage FHB; however, information on the sensitivity of Fusarium species, particularly F. poae and F. sporotrichioides, against triazole fungicides remains limited. This study assessed the sensitivity of Fusarium isolates to metconazole, tebuconazole, and prothioconazole using a 96-well microplate assay. A total of 103 isolates were collected from infected barley heads across Manitoba during the 2023 and 2024 growing seasons, including 34 F. graminearum, 34 F. poae, and 35 F. sporotrichioides isolates. F. graminearum isolates exhibited significantly lower sensitivity to all three fungicides compared with the other two Fusarium species. Median EC₅₀ values for F. graminearum were 2.1, 4.1, and 0.2 mg L⁻¹ for prothioconazole, tebuconazole, and metconazole, respectively. In comparison, F. poae and F. sporotrichioides showed lower EC₅₀ values, indicating higher sensitivity against these fungicides. Four F. graminearum and two F. poae isolates displayed insensitivity to all triazoles, with minimal inhibition of mycelial growth at the concentrations 100x higher than medium EC50 values. In contrast, no such isolates were detected among F. sporotrichioides. Molecular characterization of resistant isolates is underway to identify potential target-site mutations.

© Copyright 2025 by individual authors. All rights reserved. No part of this abstract or paper publication may be reproduced without prior permission from the applicable author(s).