Australia
July 31, 2012
Western Australian barley growers have a new weapon against powdery mildew thanks to a permit allowing them to use an alternative fungicide to combat the costly disease.
The permit comes as new research reveals the presence of a recent mutation in WA strains of powdery mildew apparently responsible for high levels of resistance to triazole fungicides, compared with other states.
The South East Premium Wheat Growers Association (SEPWA), with support from the Grains Research and Development Corporation (GRDC), has been granted one year’s conditional emergency permit approval for the use of spiroxamine (Prosper 500 EC®) by the Australian Pesticides and Veterinary Medicines Authority (APVMA).
Professor Richard Oliver, from the GRDC-supported Australian Centre for Necrotrophic Fungal Pathogens (ACNFP), said the permit provided another tool to manage powdery mildew, which caused losses of up to $100 million in WA last year.
“While dry conditions have limited the development of the disease this season, growers will nevertheless benefit from the availability of spiroxamine – a ‘Group 5’ fungicide with an alternative mode of action new to Australia,” he said.
“The availability of spiroxamine will enhance growers’ ability to manage powdery mildew.”
Professor Oliver said new research findings by the ACNFP had found that since 2010 WA strains of powdery mildew contained a mutation which strengthened their resistance to triazole fungicides.
“This explains why WA isolates of powdery mildew have uniformly more resistance to triazole fungicides than isolates in the eastern states,” he said.
“The findings highlight the importance of growers growing barley cultivars with good levels of resistance and avoiding the use of triazole-based fungicides such as flutriafol and tebuconazole.”
SEPWA president Lyndon Mickel welcomed the announcement of the permit allowing the use of spiroxamine for control of barley powdery mildew in WA, saying it gave growers another tool in the toolbox to manage the disease.
“SEPWA has been working with the GRDC to help the industry introduce new chemicals to help combat powdery mildew,” he said.
“Prosper 500 EC® provides an alternative fungicide for the control of barley powdery mildew and should help existing fungicides last longer.”
GRDC western regional panel chairman Peter Roberts said the permit for spiroxamine was providing immediate assistance for WA growers to manage powdery mildew.
“Collaboration between industry stakeholders and fast-tracking of the permit process by the APVMA helped achieve this positive result,” he said.
Mr Roberts said that in addition to the permit, WA growers would benefit from the GRDC investing $1.35 million over the next three years with the aim of supporting commercialisation of new fungicide modes of action to help manage powdery mildew.
Permit 13482 for use of spiroxamine in WA barley crops – effective until March 31, 2013 – is subject to strict rules and conditions.
More information about the permit can be found at www.apvma.gov.au/permits or download it from http://permits.apvma.gov.au/PER13482.PDF
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