Warning raised as crop diseases found in barley farms

Barley growers in the Great Southern are being warned that several diseases have started appearing in crops in the region in the past month.

Stubble-borne fungal diseases spot net type blotch and net type net blotch have been discovered on several farms across the region, and barley scald and barley powdery mildew also started to appear on some properties.

Net blotches and scald can be detrimental to crop yield, reducing grain quality and the total yield by up to 45 per cent in some cases.

Both STNB, NTNB and barley scald are primarily affecting Planet and Rosalind varieties.

The detected case of barley powdery mildew in South Stirling has also appeared on Rosalind, with Planet barley having a high resistance to the disease.

The spores can be carried in the wind, spreading the fungus to neighbouring paddocks and farms.

Department of Primary Industries and Regional Development plant pathologist Dr Kithsiri Jayasena said one of the biggest issues on the south coast was a lack of crop rotation.

“When it starts raining, the stubble from the previous year will produce the spores and it can move to the next paddock,” he said.

“The stubble-borne diseases, the pathogen can survive in the barley stubble for at least two years, so it can come up when they grow barley in the same paddock.

“Our problem in this south coast environment is that farmers grow barley and they want to keep it going until the next season to feed livestock, but the regrowth barley can produce more of the disease.

“Some who sow the crop in May, they are approaching the stem extension stage, and the disease manifestation in the crop is also dependent on what sort of fungicides they have used.”

Warm and wet conditions are ideal conditions for the fungus to appear.

“Both pathogens have built up resistance for some of the triazole-based fungicides, and if this happens, that means (farmers) have to use more chemicals to suppress these diseases,” he said.

“The fungus will produce more resistant forms, so what they have to do is at any cropping season, not use the same active compound more than twice and to use different mode of action base fungicides to manage the diseases.

“Prevention is about rotation, using resistant varieties, providing adequate nutrition, controlling green bridge and using different modes of action fungicides.”

If farmers find the disease, they can contact DPIRD Albany for advice.