The Harrington Seed Destructor is one of several technologies that provide up to 95 per cent of weed seed control.

Seed mills strike back at weed resistance

Researchers have seen up to 95 per cent control of resistant weed biotypes

Weed biotypes have an incredible capacity for developing resistance to chemical products and growers are having a tough time keeping up with the changes. Some farmers are now battling weed resistance at harvest by attaching seed mills to the rear of a combine, which gather weed seeds and damage them, preventing germination. Why it matters: […] Read more

Waterhemp weeds rise above this soybean crop in Iowa, U.S.

How intensive agriculture turned a wild plant into a pervasive weed

Science Notes: Herbicide resistance continues to challenge growers

New research in Science is showing how the rise of modern agriculture has turned a North American native plant, common waterhemp, into a problematic agricultural weed.  An international team led by researchers at the University of British Columbia compared 187 waterhemp samples from modern farms and neighbouring wetlands with more than 100 historical samples dating as far […] Read more

Using a hand-held sandblaster with projectiles to combat weeds in potatoes.

Research team looks at sandblasting-style weed control

Projectile method needs work to tackle between-row growth

A plot of white beans at Agriculture and Agri-Food Canada’s (AAFC) Harrow research farm is part of a new four-site study taking a sandblasting-style approach to weed control in Canadian crops.  “No, it’s not a joke,” begins a news release from the federal agriculture ministry about the research into what’s being called “abrasive or projectile […] Read more

If glyphosate-resistant Canada fleabane is present in soybeans, yield loss can be a whopping 65 per cent.

Fine-tuning the advice on herbicide-resistant fleabane in soybeans

Diversifiying weed control options is important, especially with glysophate costs high

As the incidence of herbicide-resistant Canada fleabane rises in central and eastern Ontario to match the southwest, so too does the awareness that targeted tank mixes and lengthened crop rotations are keys to combatting the weed in soybeans. “They’ve gotten the handle on Canada fleabane in western Ontario,” Corteva Agriscience’s Eastern Region Agronomist Marc Maisonneuve […] Read more

Agronomist Craig Reid says there are effective strategies growers can use to manage herbicide-resistant weeds, such as using longer rotations, cover crops, and tillage.

Managing herbicide-resistant weeds in corn

Planning and variety in rotations is a large factor, but cover crops and herbicide programs help too

Herbicide resistant weeds in all crops are a continuous concern, and for corn, these can be reduced with effective management practices. “The whole strategy [of weed control] is going to revolve around prevention, through rotation, tillage – or lack thereof – and soil applied, or pre-plant herbicides, followed with scouting for escapes,” says Craig Reid, […] Read more


In this photo from Mike Cowbrough’s October 2019 Pest Patrol column in Country Guide, light-green waterhemp plants approach the top of a soybean canopy after two ineffective applications of glyphosate. (Supplied photo)

Group 27 herbicide resistance arrives in Canada

Mesotrione-resistant waterhemp confirmed in Quebec

A persistent and fiercely competitive weed that has developed resistance to several herbicide groups since its arrival in Canada is now the first in the country to fight off a Group 27 product. Quebec’s Reseau d’avertissement phytosanitaire (RAP) last Friday reported a patch of waterhemp with resistance to mesotrione herbicide in the Haut-Richelieu municipality, in […] Read more

Glyphosate has become the most commonly used herbicide in the world, especially because of herbicide-resistant crops like soybeans.

Using glyphosate wisely

Glyphosate breaks down in the soil but buildup is shown to affect phytoplankton

Researchers from the University of Quebec say farmers might want to use glyphosate more sparingly — and for reasons beyond herbicide resistant weeds. Why it matters: Glyphosate may be comparatively benign, but overuse can still raise agronomic and environmental concerns. Presenting at the Innovative Farmers Association of Ontario’s annual conference, Marc Lucotte, research chair with […] Read more

Black-grass rising over and above a barley crop.

Using technology to pinpoint problem weeds

U.K. researchers create inexpensive, in-field herbicide resistance test tool

Britain’s island geography has been a major barrier for invading forces throughout history, but it’s not so effective at stopping the spread of invasive weeds. That’s why United Kingdom researchers have developed an inexpensive, convenient tool to help farmers identify resistant weeds, specifically black grass, as early as possible. Black-grass is to the U.K. what […] Read more


Bayer’s short season corn will only grow to about seven feet tall.

Bayer announces new herbicide mode of action

The broadleaf herbicide will be the first new mode of action in 30 years

A new herbicide molecule, a different approach to short stature corn and XtendFlex soybeans are three projects in the Bayer CropScience development pipeline that could have an impact on farms. Why it matters: There is increasing resistance to current herbicides so a new mode of action will be welcome. Bayer announced the new herbicide and […] Read more

Resistant waterhemp has been increasing its presence in southwestern Ontario.

Study shows multiple routes to herbicide resistance

A team including evolutionary biologists from the University of Toronto have identified the ways in which herbicide-resistant strains of invasive common waterhemp have emerged in fields of soy and corn in southwestern Ontario. They found that the resistance, which was first detected in Ontario in 2010, has spread thanks to two mechanisms: Pollen and seeds […] Read more