Assessing Fungicide Efficacies for the Management of Fusarium Head Blight on Spring Wheat and Barley

Small grains crop yield and quality losses resulting from Fusarium head blight (FHB) continue to threaten the economic sustainability of many small grains producers in Minnesota. Spring wheat breeders have made some progress in developing cultivars with moderate levels of disease resistance, but increased resistance in barley has not been achieved. Crop rotation and a timely application of fungicide remain the most important disease management strategies for managing the disease on both cropping species. Fungicide efficacy trials were conducted during 2003 and 2004 to compare the current industry standard (tebuconazole) efficacy with those of two experimental fungicides. Experimental products with active ingredients of metconazole or tebuconazole + prothioconazole significantly reduced percent FHB severity of spring wheat. Disease severity means with these experimentals averaged 28.5% less than tebuconazole, and percent visually scabby kernel means were 47% less with the experimentals compared with tebuconazole. Results were not as definitive for spring barley. Numerical trends from fungicide treatments were similar to those in spring wheat, but data were not statistically significant. These data indicate increased FHB management in Minnesota can be expected when experimental fungicides with active ingredients of metconazole or prothioconazole are registered for use on spring wheat by the EPA. The results for spring barley emphasize the urgency of achieving an effective disease management strategy for FHB and underscore the need for additional research on the disease in Upper Midwest states.