Barley leaf showing typical small brown rectangular lesions with yellow margins
Ramularia leaf spot of barley (Ramularia collo-cygni) hampers leaf development which can lead to loss of green leaf area in crops, and can result in yield loss.
Symptoms include small brown rectangular lesions with yellow margins within the leaf veins, visible from both sides of the leaf but most obvious on the exposed upper leaves after flowering. Whilst it spreads via spores to nearby hosts, evidence suggests that long distance spread is limited to infected sown seed.
Growers should be on the lookout for barley plants showing these symptoms—but note these can be easily confused with net blotch that is common on other grasses in Australia. The disease is suited to Tasmania’s cooler climate and it is most common in northern Britain.
Whilst barley is the main host of concern, Ramularia leaf spot has also been reported on oats and wheat so these are potential secondary hosts - although less likely to be impacted by the disease.
The small plot near Hagley where the disease was detected was immediately responded to with the crop removed and appropriately disposed of, as well as the site further treated to remove the fungus presence. The site remains under ongoing management and surveillance.
Biosecurity Tasmania has been advised of two additional detections in Tasmania on barley grown in spring 2016, but the advice came too late to act. Surveillance in the area will beundertaken and grain growers are encouraged to remain vigilant for signs of Ramularia leaf spot.
Biosecurity Tasmania wishes to acknowledge the assistance of the affected research groups, crop managers and land owners in reporting this disease promptly and in cooperating with the response work thus far.
What to do if you think you have found Ramularia leaf spot of barley
Barley leaf showing white mycelium on the surfaces of lesions
Plant Diagnostic Services in Biosecurity Tasmania (DPIPWE) will test barley samples suspected of being infected with Ramularia leaf spot free of charge.
Specimens or images can be submitted to a DPIPWE plant pathologist - call 1300 368 550 to be directed to a plant pathologist.
Samples of symptomatic barley leaves should be placed in sealed double plastic bags and sent to:
DPIPWE Plant Diagnostic Services
13 St John’s Avenue
New Town, TAS 7008