South Perth, Western Australia
September 13, 2005
The
potentially serious weed three-horned bedstraw has been
confirmed on two un-related properties in the Central and Great
Southern agricultural regions.
Targeted surveillance by the
Department of Agriculture,
Western Australia revealed bedstraw plants scattered over
100 hectares in the Central Agricultural region property in late
August. This was next to a 2004 barley paddock where bedstraw
was found in a harvest sample. The barley paddock was
quarantined in 2004.
The plants found recently confirmed that the
bedstraw seed present in last year’s barley sample originated
from that paddock. Infested paddocks and high risk areas will be
placed in quarantine and subjected to an eradication program.
Department weed scientist Jon Dodd said grain
samples collected by Cooperative Bulk Handling during the 2004
harvest from the affected farm and from other farms in the
district indicated that the infestation was limited to just the
one property.
Dr Dodd said Department staff had recently
carried out on-ground surveillance at the known farm and other
linked properties now that bedstraw plants were visible in crops
and fallow. To date this is the only property in the Central
Agricultural region known to have this weed.
Bedstraw plants found during the surveillance
have ranged from seedlings to flowering plants. All have a
characteristic sticky feel due to their covering of minute
hooked bristles. Fully grown plants have a straggly, scrambling
or climbing habit, with weak, branched square stems that can be
up to one metre long," he said.
In the Great
Southern region, a new infestation of bedstraw was found in an
oat crop. Dr Dodd said thorough searching confirmed the weed’s
presence in about 0.5 hectare of the crop. The affected area has
since been sprayed with glyphosate. Grain from the crop is
likely to be exported, in order to minimise the risk of
spreading bedstraw seeds to other areas in Western Australia.
“The presence
of the weed in crop-free areas within the oat crop indicates
that it was not introduced with the seed, but more likely with
feed grain that was fed out in the paddock in previous seasons,”
he said.
“In this
instance, we are conducting trace-back activities to identify
the source of the bedstraw seed that infested the crop. The
bedstraw-affected paddock will be placed in quarantine.”
This latest find in the Great Southern appears to
be unrelated to the three previous discoveries of this weed in
Western Australia.
Three-horned bedstraw is a declared weed in WA
(P1, P2 schedule). This classification
prohibits the movement of contaminated machinery. Contaminated
produce including livestock and fodder may not be
imported and all plants found must be destroyed.
Dr Dodd said bedstraw was a competitive climbing
plant similar to cleavers that formed dense masses of tangled
vegetation in crops, along fence lines and in wasteland.
“Bedstraw is a major weed of crops in
south-eastern Australia and could become a serious problem in WA
if allowed to spread in crops.
It can be controlled
by herbicides in cereals, but is more difficult to control in
canola and legume crops,” Dr Dodd said.
“An economic analysis of this weed conducted by
the Department of Agriculture in 2003 showed a cost to farmers
of weed control and foregone yield of as much as $596 million
over 12 years, if this weed became widespread and fully
established in this State.”
Colour photos to aid identification are included
in Farmnote 97/96 ‘Bedstraw’ and Farmnote 87/96 ‘Cleavers’
available from Department district offices and on the
Department's website at www.agric.wa.gov.au
Bedstraw plants will also be on display at the
Merredin Research Station Field Day on 22 September.
Suspect samples of bedstraw can be taken to the
nearest office of the Department of Agriculture for
identification or posted to AGWEST Plant Laboratories, Locked
Bag 4, Bentley Delivery Centre, WA 6983. |