Working with Western Canadian farmers to protect canola crops from clubroot
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After being the first to deliver clubroot resistance to growers, Corteva Agriscience continues to provide new genetic tools for management of clubroot in canola. With each consecutive release of new CR packages, new gene(s) and gene combinations provide protection against predominant pathotypes in Western Canada while simultaneously offering resistance gene rotation options. The latest CR packages released, CR4 and CR5, offer clubroot resistance gene stacks in various herbicide segments. CR4 delivers a new resistance gene in an effective clubroot stack in multiple herbicide segments. CR5 delivers new genes within a clubroot triple stack of a Clearfield herbicide tolerant hybrid. These options provide excellent yield, great agronomics and robust management resistance genetics of clubroot on farm while promoting CR genetics stewardship.
By Dan Stanton, Corteva Agriscience Research Scientist
I have always admired small farming communities for their ability to pull together to solve a problem using a unique blend of hard work, cooperation and “can do” attitude.
As clubroot has spread across the Prairies in the past few years, I believe it has become one of those problems that we will all need to work together to manage and correct.
Your level of familiarity with clubroot likely depends on where in Western Canada you live. While it has been on the radar of farmers in Alberta for over a decade, many growers in Manitoba and Saskatchewan have only recently become aware of this serious soil-borne disease that has infested thousands of fields across our canola-growing regions.
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Leading in seed native trait development
At Corteva Agriscience™, our efforts to combat clubroot started way back in 2004, shortly after the disease was identified outside Edmonton the year prior. As the industry leader in seed native trait development, we came out with the first clubroot resistant (CR) hybrid back in 2009 and today offer a portfolio of CR hybrids with different sources of clubroot resistance within our brands, Pioneer and Brevant™ seeds. Over the next few years, we expect to offer several more sources of CR within our Pioneer and Brevant seeds brands to provide Western Canadian farmers with even more tools to address clubroot in canola.
Working out of the Corteva research station in Ardrossan, AB, I’m part of a team of global multidisciplinary scientists and team members devoted to identifying and incorporating new effective sources of resistance into our canola hybrids. While we have been making incredible strides on this front, as a company we recently realized that we needed to do more to educate farmers on clubroot, for it’s a problem that can’t be solved by science alone.
How clubroot affects your crop
Clubroot Gall
Healthy Canola Roots
Clubroot Gall
Caused by a fungal-like micro-organism, clubroot results in distinctive club-like/galling symptoms on the plant’s roots. Water and nutrient uptake is restricted, resulting in reduced seed production and, ultimately, stunted plant growth or plant death. It has been known to cause canola growers up to 100 per cent yield loss in extreme cases. While we have been able to develop new technologies and better methods to protect against clubroot, it continues to evolve, with new virulent pathotypes found in Alberta and Manitoba.
Clubroot infection releases millions of resting spores, which can survive in the soil for up to 17 years. Because of this long lifespan, reducing the spore population in your soil is key to long-term clubroot management. This is best achieved through a proactive, integrated approach that entails preventing infestation, rotating crops and rotating effective types of CR canola hybrids.
Preventing infestation
Clubroot is spread when infested soil is carried from field-to-field by farm machinery, wind, water erosion, etc. A 2022 map identifying clubroot-infested areas shows that the disease is now widely distributed across Western Canada’s canola growing regions. This means that even if clubroot symptoms are not evident in your fields, you should assume there's a diverse pathogen population nearby.
A growing threat in Western Canada
Thousands of infested fields have been identified across canola growing regions
Clubroot affected areas in 2011
Clubroot affected areas in 2022
If you’re in prevention mode, we recommend scouting your fields early and often. Also try not to move soil between and within your fields. This can be accomplished by practicing soil conservation, working infected areas last, and always disinfecting your equipment, vehicles and boots. If you notice symptoms of clubroot, patch management may be an option, if patches are small enough. You should also keep host weeds and volunteer canola in check, ideally within 3-weeks of their emergence. Finally, increasing pH (liming) may be an option in patches or field entrances as it has been proven to reduce infection, especially in dryer years.
More importantly, do not hesitate to deploy effective CR hybrids as it’s never too early to start protecting your crop from clubroot.
Even if you don’t have the disease in your fields, clubroot resistant hybrids are proven to significantly reduce spore propagation or disease establishment compared to susceptible hybrids. CR hybrids would help prevent any initial establishment of the pathogen. Better yet, Corteva Agriscience CR hybrids yield well and are agronomically solid.
Rotating your crops
The Canola Council of Canada recommends a minimum three-year crop rotation, yet many Western Canadian farmers continue to grow wheat and canola on a two-year cycle. Now, canola is obviously a big part of our agri-economy and likely essential to how you make your living, but as an industry we must also understand that the actions we take today will affect our tomorrow.
When you utilize a one-in-three canola rotation, 90 per cent of clubroot spores in the soil are broken down, so you reduce your spore loads over time. However, with a shorter rotation, high-resting spore loads increase over time, placing additional pressure on CR genetics.
If we continue to manage clubroot at a low level, we run the risk of eroding the genetic resistance that we're developing as an industry and it may impact the sustainability of canola as a crop.
Rotating your genetics
- CR1 (1st generation clubroot resistance) remains an excellent option in fields that have never seen clubroot and where CR genetics have not been used before.
- Growers who have been using CR1 should consider rotating to alternative clubroot resistant sources. Just as we encourage early deployment of resistance in areas where clubroot might not already be, a proactive approach is the best option here as well.
- Given that keeping spore loads low is key to managing clubroot, there is no reason to wait for CR1 or 1st generation resistance to breakdown before rotating genetics.
- If clubroot has been identified on your land or close by, the goal should be to not grow the same clubrootresistance genes more than once consecutively.
- Pioneer offers a portfolio of CR hybrids with different sources and combinations of resistance gene stacks.
Tips for proactive clubroot management
- Implement a 1-in-3 year crop rotation.
- Grow clubroot resistant canola hybrids.
- Prevent and minimize moving soil.
- Control host weeds and volunteer canola.
- Scout for signs of clubroot and look for virulence shift.
- Practice patch management.
- Control pH levels in soil with liming.
A future without clubroot
The goal of our native trait development program, in terms of clubroot, is to be able to provide stacks of effective genes, as well as products with single effective genes, that will allow growers to rotate between resistance, avoid new virulence problems and provide sustainable options for moving forward into the future.
Because Corteva has been leading the industry on this for quite some time, our production is coming to maturity, to the point where within the next few years we expect to release a number of different stacked gene resistance traits that growers can rotate as part of a proactive management strategy.
That’s undoubtedly great news for everybody in Western Canada’s canola farming community. But, it’s still important to remember that clubroot resistance is a finite resource that must be managed effectively through proper on-farm practices.
It is only by working together and taking a proactive management approach that we will succeed in defending our crops against clubroot.
Thank you for reading, and thank you for being part of the solution.
Corteva - Clubroot Q&A Video
Watch Corteva Research Scientist, Dan Stanton, answer the key questions about clubroot in Western Canada and how to protect your canola. In this video, you’ll get expert advice on the following:
- What is clubroot?
- Should Western Canadian farmers be concerned about clubroot?
- How can farmers protect their crops from clubroot?
- Why should farmers practice a 1-in-3 year crop rotation?
- Why is it important to rotate genetics?
- What is CR1?
- As new sources of clubroot resistance become available, should growers continue to grow CR1 or consider rotating resistance?
- If I don’t have clubroot on my farm, is it ok to grow Corteva/Pioneer/Brevant clubroot resistant hybrids?
- When should growers grow or rotate clubroot resistant hybrids?
- What is Corteva/Pioneer/Brevant doing to protect farmers against clubroot?
- Why is Corteva/Pioneer/Brevant partnering with farmers in the fight against clubroot?