Weed Be Watchin’

Thursday, June 18, 2026

A monitoring tool for farmers & agronomists on the prairies

By Stacy Berry

Weed control of invasive plants in crops and pasture is estimated to cost $2.2 billion annually, an expense carried by farmers. However, there is a network out there that can help prevent weeds from becoming a problem for growers — if it’s used.

The Prairie Weed Monitoring Network (PWMN) is a tool farmers, agronomists, and crop input companies can use to better understand weed population shifts and predict problem weeds. Although the PWMN was formalized in 2023, “weed scientists have been monitoring weed populations for years on the Prairies,” explains Meghan Vankosky, a field crop entomology research scientist with Agriculture and Agri-Food Canada, in Saskatoon.

Vankosky is not directly involved with the PWMN; she is the chair of the Prairie Pest Monitoring Network (PPMN), born in 1997, which focuses on insect pests and is a cousin of the PWMN and the Prairie Crop Disease Monitoring Network (PCDMN), started in 2018.

On paper, although the PWMN may be the newest formal monitoring network, “most of the weed surveys have been around for decades,” says Charles Geddes, a weed ecology and cropping systems research scientist with AAFC out of Lethbridge, Alta. “The seventh set of weed abundance surveys is being completed now, and those started in the 1970s. Our herbicide resistance studies began in the 2000s, and we are looking at the fifth set now.”

What is the PWMN? According to Geddes, who is one of two co-leads on the project, the Prairie Weed Monitoring Network is a “relatively modest network of provincial, federal and academic researchers that monitor weeds across the Prairies. They conduct surveys, including weed abundance and population shifts over time, and herbicide resistance trends, as well as other value-added research. We use historical datasets to look at how the weed communities change over time, due to climate change or on-farm management choices.”

The efforts of the PWMN and the other two monitoring networks are “largely funded by the Integrated Crop Agronomy Cluster, the Government of Canada, the Saskatchewan Ministry of Agriculture Development Fund, the Sustainable Agriculture Partnership, and various crop commissions across the Prairies,” says Geddes.

Wayne Thompson of Saskatoon is the executive director of Western Grains Research Foundation (WGRF), one of the funders of the three monitoring networks. “The WGRF started supporting these networks because of the importance and value (of pest control) to farmers.”

What is the importance of monitoring pests, be it weeds, insects, or crop disease? “It all starts with information,” says Vankosky. “Farmers need timely information to support their decisions. When should they scout? What should they be on the lookout for?”

As a key part of the PWMN, Geddes is particularly concerned with weed control. “Considered on a global scale, weeds have the potential to contribute to economic losses equal to all other pests combined. These losses are in both yield and quality. Specifically, there is a growing impact of herbicide resistance in weeds across the region. The most recent survey showed that 70 per cent of crop fields in the Prairies had at least one herbicide-resistant weed present.”

The presence of herbicide-resistant weeds costs farmers. “It’s estimated that farmers spend $658 million annually, at the farm gate, directly feeling this cost, dealing with herbicide-resistance issues in weed control,” says Geddes.

Stacie Yaremko is an agronomist in Peace River, Alta., and has utilized the PWMN in her work. Yaremko especially appreciates the weed monitoring information around herbicide resistance. “Herbicide-resistant weeds are often a problem in a field long before the impacts are seen. I use the PWMN to see which resistant genotypes are popping up nearby, and to try to get ahead of the issue in places where those biotypes haven’t shown up yet.”

All that being said, what does the PWMN actually do? How does one use it? “This is a five-year project started in 2023,” explains Geddes.

“We’re quite a young network, so we are prioritizing coordinating activities, all the surveys. We also have an actively evolving website where anyone — farmers, agronomists, other scientists — can freely access all the historical datasets up to the most recent surveys, and maps.”

Having this information means “farmers can act quickly in season,” says Vankosky, which is the most crucial aspect of these networks in her opinion. “We want everyone to have accurate, unbiased, timely information. This can help farmers and agronomists prepare to respond to pest issues.”

Geddes agrees. “Understanding weed issues across the region and across time is important for managing issues — what might be on the horizon, what farmers and agronomists should be looking for.” These networks get that information into their hands, into easily understood forms.

On the ground, Yaremko finds that the forecasts provided by the monitoring networks are beneficial. “There are new weeds arriving in northern Alberta, like kochia, so it’s important to know what’s coming so we can stay on top of weed management methods to best combat those new species.”

All three monitoring networks have been around for a while, but there are always improvements to be made.

Geddes’s biggest challenge is communicating the information. “(The challenge is) taking the historical data and current data, and turning that into a digestible form. A large amount of research comes from the PWMN project, but then the problem becomes summarizing the information.

“Farmers are busy,” says Geddes. “They don’t have time to read 200-page reports put together by a group of experts deeply involved in the intricacies of the data.”

One way that they are combating this issue is an oldie but a goodie: factsheets, with help through WGRF.

Thompson: “It is so important to us to be able to provide timely information to farmers and agronomists in the growing season. Key part being that it is timely and accessible.”

Vankosky has an additional way to get information into farmers’ hands quickly. “Anyone interested in receiving Weekly Updates and Insect of the Week articles in their email can subscribe to the site, which is mobile phone friendly.”

However, Vankosky does wish they could do more surveying. “Many people wonder why we only monitor for insects at one time during the season. We go out once annually using our protocols, and it would be great to go out more often, but we just can’t — there are so many different insects, so many fields, and we just don’t have the people, the time, or the resources.”

However, the networks try to balance boots on the ground with tech. For Vankosky, “we use modelling, since insect activity is tied closely to the weather conditions. When it comes to insects, we can make quite accurate estimates based on abiotic factors.”

Thompson: “A significant effort has been made over many years to ensure the networks are providing good quality information that farmers can use. (As a funder) we always want to see the networks grow. They are effective, and we will keep supporting them because of that.”

Vankosky hopes that growers and agronomists find the networks trustworthy and useful. “The networks are working to engage with farmers, agronomists and other stakeholders – building relationships and sharing information, providing reliable, timely, updated information about pests. We hope that they trust the information and see that it is worthwhile.”

Yaremko views these monitoring networks as powerful tools, especially around weed control. “Many producers aren’t aware that these (herbicide-resistant weed) problems are so close to home, if not already in their fields. The maps are incredibly useful at increasing awareness and urgency in response to or managing these weeds.”

Farmers can access all the information gathered by these networks by visiting the websites PrairieWeeds.com, PrairiePest.ca, and PrairieCropDisease.com. However, if growers want to be more involved in how the monitoring networks operate, there is an easy way to do so. “Producer funding is already a key provider to (these networks),” says Thompson.

Geddes concurs. “Farmers already have the voice. The commissions are reviewing the proposals — getting involved in commissions and grower groups can be the way to help steer the ship and ensure these projects keep moving forward.” BF