South Perth,
Western Australia
March 10, 2006
Western
Australia’s
wheat growers are being urged to control the ‘green bridge’ of
self-sown wheat in the lead up to seeding or face a high risk of
rust disease in 2006 crops.
Each year around St Patrick’s Day, the
Department of Agriculture,
Western Australia provides a regional assessment of
potential rust risk based on the prevalence of summer rain and
subsequent green regrowth.
Department plant pathologist Robert Loughman said
the 2006 cropping season was potentially the worst for rust risk
in many years as a result of significant rainfall received in
the wheatbelt over recent months.
“Recent significant rainfall in eastern and south
eastern wheatbelt areas has emphasised the need for careful
planning ahead of the cropping season,” Dr Loughman said.
“Massive areas of self-sown wheat arising from
January rains have benefited from rainfall in early March.
Added to that, previously dry areas will now turn green and
there is a risk they will link up with existing areas of self
sown wheat.”
Dr Loughman urged growers to refer to last year’s
paddock records to help identify and manage their high-risk
paddocks for green bridge situations.
“By focusing on the paddocks most likely to be at
risk, strategic green bridge management can help reduce the risk
of local rust carry-over and considerably delay the onset of
infection in next season’s crops,” he said.
“The best strategy to reduce the rust risk is to
target rust susceptible green bridge paddocks early with a
non-selective herbicide such as glyphosate.
“For those growers with additional capacity to
control a higher proportion of volunteer plants on their
property, there will be an even greater benefit.”
Dr Loughman said paddocks carrying self-sown
Westonia, H45, Arrino and Bonnie Rock would sustain stripe rust
infections more readily than other varieties, making them the
highest priority.
Less susceptible varieties, with Crop Variety
Testing (CVT) ratings of 4, 5 and 6, possessed partial
resistance and were less prone to infection during older growth
stages.
Dr Loughman said the use of herbicide strategies
to kill volunteer wheat and starve developing rust infections
would help maximise stored soil moisture, improve weed control
and prevent build-up of cereal aphids and nematodes.
He said paddocks coming out of wheat that were
intended for a fallow or pasture in 2006 should also be reviewed
and those carrying the most susceptible varieties also targeted
to reduce rust carry-over.
For detailed information, growers could access
the ‘Plant disease forecast 2006’ from the website at
www.agric.wa.gov.au |