Symptoms and Signs
Initially, long, pale or yellow stripes appear on 2nd, 3rd, and subsequent leaves. The stripes become a darker color as the fungus sporulates on the leaf surface. As the infected plant matures, the leaves tatter (split along stripes). Infected plants usually are stunted, and produce blank (sterile) spikes. Rarely, a few seed are produced by infected spikes, and late-forming tillers may produce normal (fertile) spikes.
Comments on the Disease
Barley stripe is a problem only in barley (Hordeum spp.). The fungus is seedborne and survives in the outer layers of infected seed. Coleoptiles of seedlings are infected by the fungus under cool, moist conditions. The fungus grows systemically within the plant, produces toxins, and kills cells and discolors leaf tissue between veins, thus causing striped lesions. When conditions are wet or humid, spores are produced on the surface of leaves at about the time spikes of healthy plants in the field begin to flower. Spores are dispersed by wind to these developing spikes, germinate, and cause infections. After infection, the fungus becomes dormant in the hull or pericarp of the kernel until the seed germinates. Kernels are most susceptible to infection during early development. Moisture from rain or dew is necessary for spike infection, and plants with kernel infections are symptomless. Only one cycle of infection and spore production occurs each season.
Use certified seed. (Fields are approved for certification only if they are found free of barley stripe.)