Western Australia
October 1, 2008
Source:
GRDC's The Crop Doctor
Where cereal rusts are concerned,
the old adage ‘an ounce of prevention is worth a pound of cure’
is particularly applicable.
Among the most destructive diseases of cereals, rusts cause
significant yield loss of up to 70 per cent and quality
downgrades in susceptible varieties.
Stripe rust has been a concern for eastern states growers this
season.
The disease was initiated by susceptible early sown cereals and
exacerbated by mild temperatures and good moisture status in
early winter.
An unusually early and widespread occurrence of the disease led
many growers and their advisors to consider fungicide strategies
at crop growth stages not previously considered.
According to Dr Colin Wellings, NSW DPI plant pathologist at the
Grains Research and Development (GRDC) supported Cereal Rust
Laboratory (CRL), University of Sydney, the decision making
process for stripe rust control has been complex.
Variation in pathotype distribution, uncertainty regarding
expected variety response and some reports of fungicide shortage
were among the challenges.
Stripe rust has now been recorded in all eastern states,
including Tasmania, with recent samples received from WA.
There were reports of barley leaf rust on Baudin barley crops in
the Stirling and Gairdner regions and an outbreak of stem rust
in a 700 hectare Yitpi wheat crop at Warralakin in WA’s eastern
wheatbelt.
In the last case, disease was a classic example of green bridge
carryover where small patches of self-sown Yitpi with advanced
heading plants, spread the disease to the sown crop.
There are several take-home messages:
- choose your variety
carefully – be aware of the level of rust resistance,
- employ good hygiene
measures on your farm and destroy volunteer plants that
could act as a green bridge over summer,
- be vigilant in tracking
the course of any rust. Monitoring disease levels and
deploying appropriate and well timed fungicide strategies is
essential for containment.
Management depends on variety,
disease level and growth stage of the crop.
Early identification of rust is important as control is more
effective if applied early in the disease development.
Growers should send rust samples to AGWEST Plant Laboratories
for free identification and subsequent forwarding to CRL for
pathotype testing.
They should also inform local industry by contacting PestFax,
Email
PestFax@agric.wa.gov.au or Tel 9368 3753.
Further information on cereal rust management is available from
www.grdc.com.au/rustlinks |
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The Crop Doctor is
GRDC Managing Director,
Peter Reading |
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