Identification of Cercospora spp. on Corn in North America and Baseline Flutriafol Fungicide Sensitivity
Gray leaf spot (GLS) is an important corn disease reportedly caused by Cercospora zeae-maydis and C. zeina. Recently, flutriafol, a demethylation inhibitor (azole) fungicide, received Environmental Protection Agency registration as Xyway LFR, a product that is applied at planting for management of f...
| Veröffentlicht in: | Plant disease. - 1997. - 109(2025), 2 vom: 02. Feb., Seite 423-434 |
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| Weitere Verfasser: | , , , , , , , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2025
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| Zugriff auf das übergeordnete Werk: | Plant disease |
| Schlagworte: | Journal Article Cercospora spp. azole demethylation inhibitor etiology fungicide sensitivity gray leaf spot Fungicides, Industrial N-(2-(3-chloro-5-(trifluoromethyl)-2-pyridyl)ethyl)-alpha,alpha,alpha-trifluoro-o-toluamide F0VT7K5302 mehr... |
| Zusammenfassung: | Gray leaf spot (GLS) is an important corn disease reportedly caused by Cercospora zeae-maydis and C. zeina. Recently, flutriafol, a demethylation inhibitor (azole) fungicide, received Environmental Protection Agency registration as Xyway LFR, a product that is applied at planting for management of fungal diseases in corn, including suppression of GLS. In this study, 448 Cercospora spp. isolates were collected in 2020 and 2021 from symptomatic corn leaf samples submitted from the United States and Ontario, Canada. The Cercospora spp. were identified using multilocus genotyping of the internal transcribed spacer, elongation factor 1-α, calmodulin, histone H3, and actin genes. Based on the multilocus phylogenetic analyses, six species were identified; C. cf. flagellaris (n = 77), C. kikuchii (n = 4), C. zeae-maydis (n = 361), Cercospora sp. M (n = 2), Cercospora sp. Q (n = 1), and Cercospora sp. T (n = 3). In subsequent pathogenicity tests using selected isolates from each of these species, only C. zeae-maydis resulted in symptoms on corn, with no disease symptoms observed after inoculation with C. cf. flagellaris, C. kikuchii, Cercospora sp. M, Cercospora sp. Q, and Cercospora sp. T. Disease symptoms were observed on soybean following inoculation with C. cf. flagellaris, C. kikuchii, and Cercospora sp. Q, but not the other three species. Fungicide sensitivity of Cercospora spp. to flutriafol was assessed using a subset of 340 isolates. The minimum inhibitory concentration (MIC) to inhibit the growth of Cercospora spp. completely was determined based on growth of each species on flutriafol-amended clarified V8 agar at nine concentrations. The effective concentration of fungicide required for 50% growth inhibition (EC50) was also calculated from the same trial by measuring relative growth as compared with the nonamended control. Cercospora zeae-maydis was sensitive to flutriafol, with mean MIC values of 2.5 μg/ml and EC50 values ranging from 0.016 to 1.020 μg/ml with a mean of 0.346 μg/ml. Cercospora cf. flagellaris, C. kikuchii, Cercospora sp. M, Cercospora sp. Q, and Cercospora sp. T had mean EC50 values of 1.25, 7.14, 2.48, 1.81, and 2.24 μg/ml, respectively. These findings will assist in monitoring the sensitivity to the flutriafol fungicide in Cercospora spp. populations |
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| Beschreibung: | Date Completed 24.04.2025 Date Revised 24.04.2025 published: Print-Electronic Citation Status MEDLINE |
| ISSN: | 0191-2917 |
| DOI: | 10.1094/PDIS-03-24-0585-RE |