If the infestation is heavy, clouds of white spores will be released. These spores are dispersed by wind to healthy plants where new infections will occur. Rust has the potential to be a serious threat to all small grains. They may occur on stems but are most common on the upper surface of the leaves. When heavily infected, the whole leaf will die.
Winds can carry rust spores for great distances.
The disease can develop rapidly at temperatures between 52 and 72 degrees F when moisture is not a limiting factor. Septoria can infect all small grains. Symptoms may occur at any time during the growth of the plant and on any portion of the plant. Small pimple-like spots known as pycnidia are a diagnostic feature in older lesions. The fungus is dispersed by wind-blown rain.