Spot form of net blotch suppression and yield of barley in response to fungicide application in the Wimmera region of Victoria, Australia

Abstract

Spot form of net blotch (SFNB), caused by Pyrenophora teres f. maculata caused up to 25 % (0.9 t/ha) grain yield loss to barley and significant reductions in grain quality parameters such as retention (13 %), screenings (5 %) and grain weight (6 %) in the Wimmera region of Victoria during 2005–11. Spot form of net blotch was suppressed by varying degrees between experiments, seasons, and crop growth stages when foliar fungicide (propiconazole) was applied. Of single applications, treatment at the stem elongation (Z31) or flag leaf (Z39) growth stages generally provided the greatest disease suppression. Single application at tillering (Z25) or ear emergence (Z55) were generally ineffective. Eight chemical seed treatments registered for use in barley were tested as potential low cost management options for SFNB. Four seed treatments reduced SFNB severity in the glasshouse, but none were effective in the field.