Loose smut of barley, like wheat, is caused by the fungus Ustilago tritici ( U. nuda ). However, the particular strain of loose smut that attacks wheat does not attack barley and vice-versa. Because of the wide spread and regular use of seed treatments loose smut of barley is not common in Victoria.
Symptoms of barley loose smut are similar to those of wheat loose smut. Until ear emergence affected plants often do not exhibit symptoms. Affected heads usually emerge before healthy ones and all the grain is replaced with a mass of dark brown spores, (Figure 4.8). The spores are initially loosely held by a thick membrane that soon breaks releasing the spores onto other heads. Finally all that remains is bare stalks where the spores once were.
Figure 4.8 Loose smut of barley
As loose smuts of wheat and barley have similar life cycles see the section on the life cycle of wheat loose smut.
The Grain Trade Australia commodity standards have a maximum tolerance of 0.1 gram of smut pieces per half litre in all grades of barley.
COVERED SMUT OF BARLEY
SMUT OF OAT