In 2005 weeds were estimated to cost Australian agriculture between $2.5 billion and $4.5 billion
per annum. For winter cropping systems alone the cost was $1.3 billion, equivalent to around
20 per cent of the gross value of the Australian wheat crop. In the intervening period herbicide
resistance has become far more widespread, reducing the effectiveness of a wide range of
herbicide modes-of-action (MOAs). Consequently, any practice that can reduce the weed burden
is likely to generate substantial economic benefits to growers and the grains industry.
Of particular concern to farmers is the development of glyphosate resistance. At the time of
writing there are 24 weed species around the world that are resistant to glyphosate, with six
in Australia. There is also a large increase in species tolerant to various other herbicides, but
glyphosate in particular. This loss of glyphosate’s effectiveness is creating great concern in
industrialised farming systems globally and it is exacerbated by the widespread adoption of
herbicide resistant crops estimated at 110 million hectares in 25 countries. Until recently North
American research and extension programs have focused on herbicide solutions to herbicide
resistance problems; however, with glyphosate resistance they are being forced to look at a more
comprehensive weed management program. This puts Australian farmers in the enviable position
of having been exposed to the integrated weed management message for nearly 20 years.
Integrated weed management (IWM) is a system for managing weeds over the long term,
particularly the management and minimisation of herbicide resistance. There is a need to combine
herbicide and non-herbicide methods into an integrated control program. Given that there are
additional costs associated with implementing IWM, the main issues for growers are whether it is
cost-effective to adopt the system and whether the benefits are likely to be long-term or short-term
The manual is divided into seven sections, to assist the reader make the development of an
integrated weed management (IWM) plan a simple process.
Economic benefits of
Outlines the economic benefits of IWM in Australian cropping systems using computer model simulations.
A knowledge resource clarifying aspects of herbicide resistance in weed populations. It is crucial to understand
the basics of herbicide resistance when managing weed populations that are resistant to one or more herbicide
groups, or are at risk of becoming resistant.
benefits of weed
Discusses a range of agronomic practices that can be used to enhance the results of the specific weed
management tactics employed. It includes many simple and cost-effective management changes that can be
made to improve the competitive ability of the crop.
Tactics for managing
Provides detailed information on available weed management tactics and presents trial results from across
Australia. The tactics, sorted by Tactic Group, are addressed individually. Where a tactic can fall into two Tactic
Groups because it impacts on two stages of the weed’s life cycle, it has been grouped according to its major aim.
IWM program using
The ‘doing’ part of the manual, outlining how best to assess the on-farm situation and implement the IWM
plan on-farm. The information that should be collected for each paddock is listed, so that an effective weed
management plan can be prepared.
Profiles of common
weeds of cropping
Details the characteristics of 23 key weeds of annual cropping across Australia. Information includes basic
identification, distribution and traits that make the weed a significant problem in cropping systems. For each
weed there is a recommendation of the most suited weed management tactics for control.
Includes a number of grower case studies collected from across Australia. These are an invaluable resource
highlighting how growers are actually implementing IWM. What made them change?
What has been successful? What have been the challenges?
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