Suppression of scald and improvements in grain yield and quality of barley in response to fungicides and host-plant resistance

Abstract

Scald, caused by Rhyncosporium commune, is a common foliar disease of barley in south eastern Australia, causing significant damage during cool, wet seasonal conditions. In this study, scald caused up to 30% (1.4 t/ha) grain yield loss, reduced grain plumpness and weight by up to 25% and 20% respectively and increased screenings by up to 6%. Seed, fertiliser and foliar applied fungicides reduced scald severity and provided improvements in both grain yield and quality. Dual foliar fungicide application of propiconazole at early stem elongation (Z31) and flag leaf emergence (Z39) was most effective in controlling scald and reducing grain yield and quality losses. The seed applied fungicide, fluxapyroxad was the most effective single application fungicide treatment. Varieties with host-plant resistance had less grain yield and quality loss than the very susceptible rated variety, however, these varied between seasons. This study demonstrated that an integrated disease management strategy is required for scald in barley that includes growing resistant varieties and timely fungicide applications.