Effectiveness of fungicides with different modes of action against net blotch disease of two-rowed spring barley

Abstract

Net blotch disease caused by Pyrenophora teres is one of the most damaging fungal diseases of barley crop. This study screened comparatively the effectiveness of eleven fungicide products applied to malting barley (Hordeum vulgare L. conv. distichum Alef.) cultivar ‘Daciana’ in conditions from Transylvania. After fungicide treatment, the net blotch disease index decreased an average of 70.37-78.04% relative to untreated control. Fungicide application ensured an average of 28.66% grain yield increase, 7.51% thousand grains weight increase and 4.36% grain starch content increase relative to untreated control. Top performance was obtained by using products that contained demethylation inhibitors targeting sterol biosynthesis in combination with other active substances with a different mode of action particularly targeting mitochondrial respiration. It is a difficult task to achieve top performance on all dimensions: strict disease suppression, high quantity and quality grain yields. Preventing the occurrence of pathogen resistance to fungicide and minimizing negative effect on crop as well as remanence in the plant, are the main challenges for fungicide use and should receive further attention.