WA growers urged to think ahead and control green bridge rust disease threat

27 Feb 2017 | News

WA growers are being urged to keep paddocks clean following abundant January and February rainfall which has encouraged weed growth and the creation of a ‘green bridge’ which can host rust and other diseases and pests.

Department of Agriculture and Food WA plant pathologist Geoff Thomas said that a break without weeds of at least a monthprovides improved control and potential yield benefits, significantly reducing the risk of rusts and other disease and pest threats such as powdery mildew, viruses or aphids.

“It is critical that growers eradicate the green bridge as rust pathogens rely on green leaf material to survive and pass onto crops in the following season,” Mr Thomas said.

“Growers must be vigilant and look for rust-susceptible weeds and crop volunteers not only in paddocks, but along fence lines, around sheds and silos. At least a month of no green growth is required to prevent disease survival.”

Mr Thomas said rust is a social disease and encouraged growers to take collective action to minimise an early outbreak of rust and reduce disease pressure.

“In 2016, barley leaf rust was reported widely across the Western Australian wheatbelt, extending from the Esperance and lower great southern regions where it occurs regularly to the central and lower north regions as well,” he said.

“Regrowth of susceptible varieties such as Bass are a high risk for carry over of barley leaf rust and should be targeted as high priority.”

There were also a few instances of wheat leaf rust late in the 2016 season, with the pathotypes identified by the University of Sydney’s Plant Breeding Institute as the recent incursions with increased virulence on popular local varieties such as Mace.

Should growers find rust on volunteer cereals or grasses, they are encouraged to send samples for pathotype analysis.

“Leaf rust withstands summer temperatures better than stripe rust, so with a combination of high levels of the pathogen and most common wheat varieties having some degree of susceptibility, there is certainly a likelihood of leaf rust carrying over to 2017,” Mr Thomas said.

“In regions where regrowth is widespread and remains uncontrolled until seeding of this seasons crops, choice of more resistant varieties and utilisation of registered fungicides at seeding will be beneficial.”

 

WA Contacts

Central Agricultural Region
Geoff Thomas
Plant Pathologist
Dept of Agriculture & Food, WA

Northern Agricultural Region
Ciara Beard
Dept of Agriculture & Food, WA

Southern Agricultural Region
Kith Jayasena
Dept of Agriculture & Food, WA