Overview: Rusts are important diseases of barley which can cause severe crop damage in susceptible varieties when conditions are conducive. There are four rusts which can attack barley:
- leaf rust (caused by Puccinia hordei ) is the most common
- stem rust (caused by Puccinia graminis ) is less common but can cause severe crop loss in favourable years
- barley grass stripe rust (causal pathogen currently unnamed) is common and infects some susceptible varieties
- barley stripe rust (caused by Puccinia striiformis ) is an exotic disease.
Leaf rust occurs most years in susceptible varieties, especially in high rainfall regions. Early infections (July – August) can result in yield losses of up to 20 percent. Stem rust is potentially the most devastating disease of the rusts and is able to cause complete crop loss in the rare event where conditions are suitable for a severe outbreak. Barley grass stripe rust is common but unlikely to cause yield loss in susceptible varieties when conditions are favourable. The exotic pathogen barley stripe rust will cause severe losses in most varieties if it is introduced to Australia.
POWDERY MILDEW OF WHEAT