[ASC-media] WINNING THE WEED WAR
brendon at iinet.net.au
Wed Jan 30 03:56:34 CET 2008
GRDC Media Release 30.1.08<?xml:namespace prefix = o ns =
WINNING THE WEED WAR
Winning the war against weeds is a long-term campaign because the real
enemy, the seed, lies hidden in the soil.
This is one of the messages of a national project funded by the Co-operative
Research Centre for Australian Weed Management.
To win the war, growers need to target the weed seedbank beneath the ground,
as well as the weeds growing above it.
At a direct cost to Australian farmers of $1.5 billion per year, with lost
agricultural production estimated at more than $2 billion per year, it is a
war worth winning.
Results of a Grains Research and Development Corporation (GRDC) supported
study by Department of Agriculture and Food WA (DAFWA) researchers, compiled
and reviewed by Peter Newman, demonstrated that a wild radish seed bank can
be eroded by 95 per cent over four to five years of complete or almost
complete seed control.
This equates to approximately 50 per cent decline of the seedbank each year.
Dr Rohan Rainbow, Manager, Crop Protection, GRDC said that wild radish has
the potential to be even more significant than annual ryegrass because the
seeds have dormancy and protective mechanisms, making them difficult to
The way forward is to use Integrated Weed Management (IWM), which is a
modern, long term and sustainable approach, using a wide range of control
options, he said.
Dr Rainbow indicated that single use techniques, such as repeated use of the
same herbicide, increases the risk of herbicide resistance.
IWM uses a range of control techniques that recognise the ecology of the
weed and its environment and aims to bring the weed population down by
depleting the seed bank.
Dr Rainbow emphasised that IWM is a long-term approach involving a five to
10 year weed reduction strategy, rather than a short-term response to
current seasonal events.
One way to understand, predict and manage weeds is to use a model to
integrate knowledge from a large number of trials to build a representation
of the way weeds work over a longer time frame, given a wide range of
A recently developed CRC for Australian Weed Management prototype, aptly
named Weed Seed Wizard, is a work in progress developed by co-project
leaders, Dr Michael Renton from the University of Western Australia and Dr
Sally Peltzer of DAFWA.
According to these researchers, the weed seedbank is a formidable opponent
to farmers because it is invisible, patient and hard to understand.
Dr Renton, a mathematical modeller, said that the Wizard provides a window
into parts of the system usually hidden (the seedbank) and a look at how
they influence and are influenced by parts of the system that affect growers
(the weeds) and the parts growers can control.
We want this model to be the basis of a practical decision-aid tool to help
farmers and consultants manage weed populations in real farming contexts and
determine optimal control measures, he said.
The simulation is specific to the individual site, season and weed species.
The model simulates important aspects of the interaction between weather,
paddock management and seed biology, in order to track and predict the
numbers, ages, soil depths, dormancy levels, viability and germination of
seeds in the soil.
Weed Seed Wizard is currently programmed for six weed species common in
farming systems in WA: barley grass, ryegrass, wild radish, wild oat, brome
grass and silver grass.
The program is structured so that emerging weed species and newly developed
management options can be easily added to the model, which will be released
Information on weeds and the Integrated Weed Management manual is available
at HYPERLINK "http://www.weeds.crc.com.au/"www.weeds.crc.com.au
The Weed Seed Wizard prototype can be downloaded from
Authorised by GRDC and issued on its behalf by Brendon Cant & Associates,
Tel 08 9384 1122
Dr Rohan Rainbow, Tel 02 61664500
Dr Sally Peltzer, Tel 08 9892 8504
Dr Michael Renton, Tel 08 6488 1959
Peter Newman, Tel 08 9956 8563
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