Evaluation of different fungicides for control of fusarium head blight in wheat inoculated with 3ADON and 15ADON chemotypes ofFusarium graminearumin Canada

Fusarium head blight (FHB) continues to threaten the economic sustainability of many small grain producers in Manitoba by causing losses in grain yield and quality. In this 2-year study, four fungicides were tested on two spring wheat cultivars with different levels of resistance to FHB inoculated with 3ADON and 15ADON chemotypes of Fusarium graminearum. All fungicides (prothioconazole, tebuconazole, metconazole and prothioconazole+ tebuconazole) reduced FHB index, per cent Fusarium-damaged kernels (% FDK) and deoxynivalenol (DON) levels and increased yield compared with the non-sprayed control in the moderately resistant cultivar 'Glenn'. In the highly susceptible cultivar 'Roblin', all fungicides reduced FHB index and increased yield compared with the non-sprayed control; however, inconsistent results were observed for FDK and DON. Differences were observed between the two chemotypes for all variables in both years except for FDK and yield in 2010. This study confirmed that host resistance plays an important role in host-pathogen-fungicide interaction. Therefore, the combined effect of growing moderately resistant cultivars with fungicide application can reduce damage caused by FHB even under high FHB severity.