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This fact sheet provides information for weed managers who control volunteer canola plants on roadsides, rights-of-way and other non-agricultural settings.
Many weed managers rely on glyphosate to control roadside weeds, including canola. Glyphosate will not control Roundup Ready® canola. However, Roundup Ready® canola volunteers can be effectively controlled using other herbicides or standard non-chemical weed control measures.
GM canolas approved for commercial release in Australia are:
- Roundup Ready® canola, tolerant to the herbicide glyphosate
- InVigor® hybrid canola, tolerant to the herbicide glufosinate ammonium
- InVigor® x Roundup Ready® canola, tolerant to both glyphosate and glufosinate ammonium.
These GM canolas were assessed as no more invasive or persistent than conventional canola.
Currently, only GM glyphosate tolerant canola is grown commercially in Australia
, and only in New South Wales, Victoria and Western Australia.
Roadside canola volunteers
Spilled harvested canola can result in ‘volunteers’ just like any other harvested seed product.
Volunteer canola populations occur where seeds spill during transport and handling, eg. along roadsides and railways and at receival points. Canola competes poorly with perennial grasses and other perennial vegetation and rarely persists in large numbers on roadsides in Australia. Roadside canola may sometimes set seed, resulting in new plants. However, roadside populations are generally short-lived and perpetuated by new spills each year.
Managing roadside Roundup Ready® volunteers
Control of Roundup Ready®
canola can be achieved using integrated weed management (IWM) practices. Options include:
- a knockdown herbicide other than glyphosate
- mechanical control, such as mowing, slashing or chipping
- an approved tank mix of glyphosate with another herbicide that controls brassica weeds.
All herbicides must only be used in accordance with the approved label instructions [unless authorised under relevant legislation for specific ‘off-label’ use]. Care should always be taken with herbicide choices to ensure that they will effectively control targeted weeds and are appropriate for the location.
Managing herbicide resistance
Reliance on glyphosate as the sole weed management option may contribute to the development of glyphosate resistant weeds eg. annual ryegrass. To help prevent this, survivors of herbicide treatment should be controlled by a mechanical method or an alternative herbicide. Adopting IWM practices, including rotation of herbicides, is important in managing both roadside canola volunteers and other weeds.
For more information:
- The APVMA is responsible for registering herbicides for use in Australia; (02) 6210 4700
- CropLife Australia is the peak industry body for the oversight of Resistance Management Strategies included on crop protection product labels; (02) 6230 6399
- Office of the Gene Technology Regulator (OGTR) is responsible for the assessment and approval of genetically modified organisms (GMOs). Information about the approval of Roundup Ready® canola and other GMOs is available from the OGTR website or 1800 181 030
- The Australian Glyphosate Sustainability Working Group has information on managing herbicide resistance and IWM.
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