Stay Ahead of Weeds This Year

Tuesday, April 21, 2026

Advisors flag the most troublesome weeds for 2026

By Mary Loggan

Prairie farmers are once again gearing up for a familiar fight: a long list of problem weeds that can steal yield, tie up equipment and add real dollars to the cost of production if they get ahead of you early. From herbicide-resistant kochia to wild oats and volunteer canola, the pressure is constant, and the window to act can feel shorter every year.

This spring, crop advisors say the farms that stay ahead of the weed spectrum will be the ones that treat weed control as a year-round system, not a single pass — with planning, timing and diversity forming the core of effective weed management in 2026.

Top weeds

In the North Peace region of Alberta, Scott Schaffert, Certified Crop Advisor (CCA), says long familiar weeds are now sharing space with a new problem.

“The most common weed in the North Peace is lambsquarters. In a dry year, lambsquarters develop a thick, waxy cuticle layer that makes it hard to control with herbicides, especially Liberty. But in terms of the weed to watch, it would have to be kochia.

“For 30 years, I always heard that kochia was a southern Alberta weed, and nothing to worry about way up here. Well, it turns out it is here and increasing.”

In central Alberta, Steve Cowan, CCA and agronomist with Crop Management Network, says the dominant issue remains resistant wild oats.

“For Central Alberta, Group 1 and 2 resistant wild oats remain our biggest challenge.

“While we’re seeing increasing pressure from weeds like kochia moving into the region, the most challenging and yield robbing weed we deal with is still herbicide resistant wild oats.

“Until a few years ago, I think many in the industry had been in a bit of denial that these escapes were truly resistance related, which allowed the problem to quietly grow.

“Now that it’s clearly established, it has become the dominant weed management issue in Central Alberta.

“Beyond herbicide resistance, we’re seeing increasing pressure from weeds like kochia and foxtail barley, both of which can survive saline conditions.

“Salinity has become more prevalent in many fields in Central Alberta, I think, because of several drier years where we have gained back some lower land.”

In southern Saskatchewan, CCA Braelynne Heck sees resistant broadleaf weeds and wild oats as defining issues.

“From a weed management perspective, herbicide resistant broadleaf weeds remain a dominant challenge across the Prairies, along with Group 1 and Group 2 resistant wild oats.

“Resistance continues to limit in crop control options and increases the importance of pre seed planning and crop rotation.”

She notes that in southern Saskatchewan, where pulse crops make up a large part of rotations and in crop options are limited, effective weed control and resistance management are critical for long term success.

Kochia, she adds, remains the most widespread challenge in southern Alberta and Saskatchewan because of its early emergence, high seed production and tumbleweed spread, backed by drier conditions, adaptability and poor herbicide use.

In the southwest corner of Manitoba, Emily Elliott, CCA and field advisor with Enns Brothers out of Melita, links current concerns to how 2025 ended.

“I think for a lot of the province we ended the season with a favourably wet and open fall. These conditions are important to consider as we look forward to the 2026 growing season.

“Winter annual weeds like flixweed, stinkweed, shepherd’s purse had a great start due to the fall moisture.

“Some of our tougher perennials, including Canada thistle, dandelion and foxtail barley, also would have had a great fall for germination and new growth.”

On fields without fall weed control, she says, growers should expect a heavy spring flush.

“Kochia is also always on our radar because it’s so good at growing in a vast range of conditions. We also need to remember there is a lot of moisture in the ground, so even if we have a cold and dry spring, there will be some moisture to get weeds started into growth.”

In Shaunavon, Sask., Rahulkumar Patel, CCA and agronomist with Pioneer Co op, expects kochia and wild oats to be the most challenging weeds.

He says climate and cropping practices are favouring tougher weeds.

“The persistence of drought can make it a challenge to grow good crops every year. This semi-arid region receives an average of 12.75 inches of rainfall.

“Due to climate change, we are facing challenges of dry fall every now and then over the last nine years.

“Weeds, winter annuals, and spring annuals develop greater drought tolerance and try to overcome herbicide application by developing resistance to G14, G4, G2 kochia resistance or stinkweed G2 resistance, or wild oats G1 and G2 resistance.

“Also, due to short rotation, lentil-durum wheat and repeated use of G1 Fop MoA herbicide are creating a wild oats resistance population in general.”

Specific management challenges

In the North Peace, Schaffert says timing often undermines otherwise solid programs.

“Kochia became a hot topic in 2025, so more growers will be on the lookout for it. The big issue up here is that the best control of kochia comes with early application (1-4 leaf stage), with control levels dropping off as the plant gets bigger.

“Seeding takes precedence as soon as you can get on a field. A pre seed application often becomes a post seed pre emergent or even a ‘ran out of time non application.’ So that puts a lot of pressure on your in crop herbicide to perform.”

Cowan stresses that herbicide resistant wild oats will demand longer term thinking and tighter execution.

“The challenge with herbicide resistant wild oats is that this issue wasn’t created in one season, and it won’t be solved in one season.

“We sprayed our way into the issue, and unfortunately, we won’t be able to spray our way out of it. So, managing herbicide resistance will require a multi pronged management approach.

“For years, new herbicide technology helped delay resistance, but that pipe-line has slowed, and there isn’t a ‘magic bullet’ coming.

“As a result, we need to preserve the herbicide actives that are still effective and make sure that every time they are applied, we give them the best chance to perform — being mindful of environmental conditions, following label best use guidelines (water volumes being a key one), being mindful of water quality, watching what products get thrown in the tank with the herbicides and how that affects performance.”

He says 2025 showed how much the environment can undercut good chemistry.

“One key lesson from 2025 was how strongly environmental conditions, in this case, very low humidity, impacted herbicide performance. It also reinforced that the right adjuvant strategy can improve efficacy when applications must be made under less-than ideal conditions.

“The use of adjuvants to increase efficacy even slightly is a great example of how we can manage the technology we have, to keep it effective longer.”

Elliott points to 2025’s late rains as an example of how even good plans can be tripped up by weather.

“Canopy closure and early control are key for weed control. In 2025, we had a lot of late rains that spurred lambsquarters escapes in canola.

“We also need to make sure we are timing the application well, using appropriate tank mix partners, and watching weather factors.

“We still need to get the field spray-ed in the window, so sometimes we do have to push in less than ideal conditions.”

For Patel, the combination of late harvest and existing rotations made it difficult to use residual products to set up 2026.

“Due to late harvest in this region, farmers were not able to carry out fall residual herbicide application in a timely manner to manage weeds for the next season.

“Group 1 and Group 2 resistant wild oats could be a major issue for farmers to combat it with a G15 herbicide product like Avadex in spring, which will be difficult due to the lack of snow this year.”

Planning ahead

Planning for 2026, Heck outlines a layered approach.

“Adding a herbicide with a different mode of action, preferably with residual control, such as a Group 14 or Group 15, to a pre seed glyphosate burn off can make a significant difference in controlling resistant weeds.

“Post harvest applications of a Group 4 herbicide can target winter annuals like wild mustard, stinkweed, and flixweed, as well as perennials such as Canada thistle and dandelion, preventing them from setting seed and reducing future pressure.”

She says layering herbicide groups with strong crop rotation helps balance both economic and agronomic goals, and that sustaining innovation in herbicide development while using existing products responsibly will be critical over the next decade.

Cowan agrees that herbicide resistance will remain a defining force.

“Herbicide resistance will continue to shape weed management in Alberta over the next five to10 years.

“It’s more apparent with wild oats because our herbicide options are more limited, but we have many Group 2 resistant broadleaf weeds as well.

“As we continue to rely on other groups to control those weeds, I’m sure we will continue to see further herbicide resistance to those groups in the future and, with fewer new actives coming down the pipeline as I mentioned earlier, we will continue to lose ‘bullets in the gun.’”

He says soil applied residual tools and getting more out of the crop itself will be key.

“Soil applied residual herbicides are one of the key tools we’re focused on, as they introduce additional modes of action to help manage resistance.

“However, they require moisture for activation, can be influenced by organic matter levels, and demand more planning than the simple post emergent programs many growers are used to.

Developing practical best management guidelines will be important to make these tools perform consistently, he notes.

“We’re also putting more emphasis on using the crop itself as part of the weed management strategy.

“Increasing crop competitiveness through variable rate seeding, fertilizer placement to promote strong early vigour, and reducing emergence losses — including exploring pelletized gypsum in the seed row to help in sodic soils as an example — are all areas of interest.”

He adds that water quality, temperature, humidity and spray timing all influence herbicide performance, and that understanding how to adjust water volume, manage water quality and choose the right adjuvant package when conditions are less than ideal is increasingly important.

Early weed removal and a strong pre seed burn off remain, in his view, some of the most important passes the sprayer makes.

Elliott brings the focus back to fundamentals and gradual change.

“Spray timing is also super important, especially in the early spring. We need actively growing weeds to have success.

“Watch the temperatures. If it froze, you might have to hold off spraying until enough time has passed for weeds to be actively growing again.

On the product side, she encourages growers to rotate chemistry and add soil applied tools where they fit.

“Make sure you are trying new herbicides on the market with different actives or groups than you always use in your program.

“The worst thing we can do is overuse one group. When we do this, we generally just lose the efficacy of this active and create bigger issues.

“This is becoming a more common practice, but using soil applied herbicides to stop weed seed germination is also a great tool we have.”

She says crop rotation will always be important for weed pressure.

Patel advises building detailed herbicide group strategies around moisture and crop plans.

“Farmers must consider the rotation of herbicides MoA on their fields every year and consider the layering of herbicides concept in their crop plan instead of using the same mode of action herbicides in their fields to create issues of resistance.”

He is also promoting a wider range of agronomic tools focused on weed pressure.

“I am encouraging and educating farmers to add cover crops in rotation to manage weed pests, and the use of biologicals like mycorrhizae to manage Russian thistle could be an alternative tool, along with herbicide management, in the future.” BF