Impacts of crop production factors on fusarium head blight in barley in eastern Saskatchewan

Fusarium head blight (FHB) in barley (Hordeum vulgare L.) is well established in the eastern Canadian Prairies and appears to be moving westward. A survey of 192 barley crops in eastern Saskatchewan was conducted to determine the impact of agronomic practices on FHB (1999-2002) and Fusarium-damaged kernels (FDK) (2000-2001). The most common species isolated from spikes and kernels were F. sporotrichioides, F. avenaceum, and F. graminearum, followed by F. poae and F culmorum. Disease tended to be higher under minimum-till compared with conventional- or zero-till. Fusarium sporotrichioides was favored by a previous cereal crop, whereas F avenaceum was higher after a pulse crop, and F graminearum decreased after a pulse but not an oilseed crop. The latter two pathogens were also more prevalent after diversified cropping sequences than after two cereal crops. Summer fallow, or summer fallow alternated with cereals, decreased FDK. Previous glyphosate (Group 9 herbicides) use was associated with increased infection by all Fusarium spp., whereas Group 1 herbicides were associated with increased infection by F poae and F sporotrichioides. Effects of both herbicide groups depended on tillage system. Number of previous glyphosate applications was also correlated with FHB caused by F. avenaceum and F. graminearum. We concluded that in eastern Saskatchewan, barley grown under minimum-till where glyphosate had been sprayed and following diversified cropping sequences would sustain the greatest damage due to FHB and FDK caused by F avenaceum and F. graminearum.