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South Perth, Western Australia
August 21, 2007
 Farmers
are advised to examine their crops for signs of stripe rust and
Wheat Streak Mosaic Virus (WSMV) after the first detections of
these diseases were reported to the
Department of Agriculture
and Food last week.
Stripe rust
was found on a property south of Cunderdin in a Calingiri wheat
crop, while WSMV was found in a wheat crop growing south of
Koorda.
Department
plant pathologist Geoff Thomas said the discovery of stripe rust
this year was later than the first cases in the 2006 season,
which were reported in July.
“However, it
is still early enough in the season for the disease to cause
significant crop damage,” he said.
“Additionally,
late planting of crops in many areas has meant they are still at
the vulnerable stage for rust infection, even though they may be
an intermediate or moderately resistant variety.”
Mr Thomas said
he recommended that farmers closely monitor crops for the
presence of stripe rust, particularly susceptible varieties and
those without seedling fungicide protection.
“Farmers who
find stripe rust in their crops at early growth stages should
immediately consider a foliar fungicide spray,” he said.
Department
plant virologist Brenda Coutts said in relation to WSMV, the
only known control options were controlling the ‘green bridge’,
sowing healthy seed stocks of wheat and avoiding early sowing
when temperatures favour wheat curl mites.
“Symptoms of
the virus include pale and green streaking on the leaves with
yellowing of leaf tips and stunted and tufted growth. The
streaking is usually most obvious towards the basal half of the
leaf,” she said.
“WSMV was
first found in WA at low levels in 2006 on properties throughout
the wheatbelt.
“The disease
can be introduced to crops by planting infected seed stocks, and
is spread by means of a vector mite, the Wheat Curl Mite (Aceria
tosichella).
“However,
there is no effective within crop chemical control measure for
either the mite vector or virus and no WSMV-resistant wheat
varieties available.”
Ms Coutts
recommends that farmers monitor crops and if they suspect WSMV
then plant samples can be sent to AGWEST Plant Laboratories for
confirmatory testing (chargeable). It is also suggested seed
harvested from infected paddocks be tested before being sown
next season.
More
information on WSMV and wheat curl mite is available from NSW
DPI -
PrimeFact 99, WSMV and wheat curl mite and for more
information on stripe rust visit
www.agric.wa.gov.au and search for
Managing stripe rust and leaf rust of wheat. |
