Biofungicides as a sustainable strategy to combat common bunt (Tilletia caries and T. laevis) in winter wheat

Common bunt, caused by the seed-borne fungal pathogens Tilletia caries and T. laevis, remains one of the most economically important diseases of winter wheat in Europe. The objective of this study was to evaluate the efficacy of seed treatment products permitted for use in organic farming in the Czech Republic against common bunt. Small-plot field experiments were conducted over four growing seasons at Prague-Uhříněves, Czech Republic (Central Europe). Winter wheat seeds were artificially inoculated with Tilletia spp. prior to sowing. Six seed treatment products representing biological and chemical suppression approaches were tested. Disease assessments were performed according to standardized European and Mediterranean Plant Protection Organisation (EPPO) guidelines. Plant emergence was recorded, and the total numbers of healthy and diseased tillers were counted. Plant emergence, disease incidence, and treatment efficacy varied considerably among growing seasons. The lowest plant emergence was observed in plots treated with Tillecur, although this reduction was statistically significant only in 2023/24. Across all years, Tillecur consistently provided the highest level of disease control. Under conditions of lower pathogen pressure, the biological products Polyversum and Gliorex also demonstrated effective suppression of common bunt. These results highlight the importance of effective seed treatments against Tilletia spp. for sustainable and resilient organic wheat production.