Spot form of net blotch, caused by Pyrenophora teres f. maculata, is the most prevalent foliar disease of barley in Victoria, Australia.
Surveys of incidence and severity of foliar diseases in a total of 127 barley (Hordeum vulgare) crops throughout Victoria were carried out during 2007 and 2008. In each crop, 100 tillers were assessed for disease symptoms on the top four leaves. Spot form of net blotch caused by Pyrenophora teres f. maculata had the highest incidence, being present in more than 90% of crops surveyed, with severity ranging from 0 to 42%. Scald caused by Rhynchosporium secalis had the second highest incidence, being found in 13 and 23% of crops in 2007 and 2008, respectively, with severity ranging from 0 to 16%. Leaf rust caused by Puccinia hordei was present in 13 and 18% of crops in 2007 and 2008, respectively, with severity of up to 3%. Powdery mildew caused by Erysiphe graminis was present in 11 and 9% of crops in 2007 and 2008, respectively, with severity below 0.1%. No other diseases, such as the net form of net blotch caused by P. teres f. teres were detected. The high incidence of spot form of net blotch, which can cause up to 44% grain yield loss, suggests that resistance traits need to be made a priority and targeted by barley breeding programs in Victoria for control of this important disease.