Crown Rust - Oats

Scald (Rhynchosporium secalis) is a common disease of barley which can result in significant yield loss if not controlled. Scald is favoured by cooler, moist conditions with the initial source of inoculum being infected straw debris. The first symptoms often appear during winter or early spring, initially as pale greyish lesions which then develop a more straw coloured appearance with a defined dark edge to the lesion.

Stem rust (Puccinia graminis) is a disease that has many species specific strains. The strain that infects ryegrass in New Zealand does not attack other species such as wheat or barley. Stem rust is favoured by warm conditions and is at its most aggressive later in the spring. Not controlled, stem rust will lead to major economic losses.

Leaf rust (also known as brown rust) is a disease of barley. Whilst occurring less frequently than leaf rust in wheat it can result in significant yield loss if not controlled. Leaf rust is favoured by warmer, drier conditions with the initial source of inoculum being infected volunteer cereals. Under favourable conditions leaf rust can develop very quickly. Spores are scattered at random on the leaf and are often surrounded by a pale chlorotic halo.