What Is Resistance?
Herbicide resistance is the elephant in your field. It's the weed species' ability to survive and reproduce even after exposure to a rate of herbicide that would normally be lethal. For a weed to be considered resistant it must:
- Normally be controlled by the herbicide
- Survive a usually lethal dose of the herbicide
- Be heritable, meaning it is passed from generation to generation
Resistant weeds thrive on routines so breaking the cycle that enables weed resistance to develop is critical to addressing this potentially devastating problem. Crop rotation and introducing different herbicide mode of actions are all part of an effective resistance management strategy.
Keep in mind that herbicide-resistant individuals are naturally present within a weed population at very low frequencies.
LibertyLink System – A Unique Resistance Management Tool
The unique offering of the LibertyLink® system – including some of the highest yielding InVigor® canola hybrids in combination with Liberty herbicide – gives you one of the best resistance management tools to choose from.
- Liberty is the only Group 10 herbicide used for in-crop weed control on canola
- Liberty is an excellent alternative to glyphosate, helping manage risk of Group 9 resistance in Canada
- When Liberty is tank-mixed with Centurion®, you get 2 modes of action attacking grassy weeds, further helping delay herbicide resistance
Why Is It Important To You?
The management issues and yield concerns with herbicide resistance are very real, especially now with glyphosate-resistant kochia identified for the first time in Western Canada in 2011.
Dr. Hugh Beckie with Agriculture and Agri Foods Canada has said, "Glyphosate has likely delayed the evolution of weed resistance to other herbicides and mitigated their resistance impact. However, farmers need to think carefully about how and when they use glyphosate."
Discover how canola farmer David Torrie has taken effective steps to address resistance in his field.
A Growing Problem Across Western Canada
Glyphosate resistance has been confirmed in all three Prairie provinces. The alarming news is that its rate of incidence continues to increase. Western Canada is still in the early stages of glyphosate resistance. That’s why it’s so important to take action now by adopting effective resistance management practices to slow down the number of acres affected by glyphosate resistance. Check out the map below to see how much glyphosate-resistant kochia has spread since 2011.
Herbicide Resistance – What's The Impact To Farming In Western Canada?
Loss of viable herbicide options
- Have to rely on currently available herbicides for the foreseeable future
- No herbicides with new modes of action are in advanced trials
Would require changes in weed and crop management practices
- Zero or reduced tillage rely heavily on herbicides for weed control
Reduced return on investment
- Increase the cost of weed management
- Loss of yield potential
The number of weeds with herbicide resistance continues to rise
- Including weeds resistant to multiple modes of action
How Does Herbicide Resistance Develop?
The image below demonstrates the interaction between a weed species and a particular mode of action and the development of herbicide resistance at different speeds. It’s clear to see that over time the use of a herbicide from the same group quickly changes from being very effective to becoming extremely ineffectual. In fact, by the fifth year of application the herbicide is failing to eliminate the majority of weeds because they are resistant to that group of herbicides. What is particularly alarming is the dramatic increase in failure rate from the fourth to fifth season.
Development of Herbicide Resistance
||% Resistant Weeds in Population
Source: Weed Science Society of America, 2011
What Can You Do To Delay The Onset Of Herbicide Resistance?
- Don't rely solely on herbicides for weed control
- Develop field-specific long-term weed management plans
- Rotate both crops and herbicides
- Use clean seed
- For more tips on managing herbicide resistance, visit MixItUp.ca
General guidelines for herbicide rotations:
- Avoid repeated use of the same herbicide or herbicides having the same mode of action in the same field year to year
- Limit the number of applications of a single herbicide or herbicides having the same site of action in a single growing season
- Use mixtures or sequential treatments of herbicides having different modes of action which are active on the same target weeds whenever possible
- Use non-selective herbicides pre-seed or pre-emergence to control early flushing weeds (prior to crop emergence) and/or weed escapes
Herbicide resistance is everyone's problem. This product is a Mix It Up solution.
Visit MixItUp.ca for more simple strategies and solutions.