Fusarium head blight (FHB) is one of the most important diseases of cereals. Several foliar fungicides have been used to manage FHB in North America. Fungicide trials were conducted in Winnipeg and Carman from 2018 to 2020 to evaluate the efficacy of different application times of the fungicide prothioconazole + tebuconazole for the mitigation of FHB incidence, severity, index, Fusarium-damaged kernels (FDK), and deoxynivalenol (DON) in winter rye. Treatments consisted of an inoculated-untreated check (IUC), an uninoculated-untreated check (UUC), and fungicide applications at heading, 10% anthesis (10A), 80% anthesis (80A), and 6 days after 50% anthesis (6DA50A). Fungicide application at 10A resulted in the highest efficacy for reducing FHB incidence, severity, index, FDK, and DON content in winter rye. Fungicide applications at 10A and 80A increased yield compared with the IUC. Fungicide applications at 10A, 80A, and 6DA50A reduced ergot severity for KWS Serafino compared with the IUC. Correlation analysis revealed strongly positive associations among FHB traits and negative correlations between these traits and thousand-kernel weight or test weight. As the first study of fungicide efficacy for FHB in winter rye in Canada, the results provide winter rye growers with important information on the use of fungicides to manage FHB.
Wang et al. (Thu,) studied this question.