GFM Network News


Rough-stalk bluegrass in wheat, and a closeup (inset) of the open panicle of rough-stalk bluegrass.

Pest Patrol: What was that grassy weed in my winter wheat at harvest time?

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Three different types of grassy weeds were found above the winter wheat canopy at harvest this year. To prevent them from becoming a problem, they need to be identified so that the appropriate management actions can be taken. Here is a breakdown of each grass species and its control options:  Chess (Bromus secalinus) Chess grass […] Read more

Figure 1: A field of winter wheat where bluegrass has headed at the same time.

Pest Patrol: Bluegrass management in winter wheat

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Yield losses of more than 50 per cent can occur from bluegrass competition in winter wheat. As well, because bluegrass species often head at the same time as winter wheat, they could intercept and reduce the amount of fusarium head blight fungicide that actually reaches the grain head (Figure 1 at top).  There are several […] Read more


Figure 1 (left). A bolted Canada fleabane plant the day following a frost event where nighttime temperatures reached -3.3 C; Figure 2 (right). The same bolted Canada fleabane plant the following spring (March 2021).

Pest Patrol: Canada fleabane in an organic hay crop

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Q: I have a lot of Canada fleabane in my organic hay crop. Is it a problem to feed? How do I get rid of it? It’s not great to have Canada fleabane in your hay crop. It’s an alternative host for plant feeding insects such as tarnished plant bug, and the leaves have irritated […] Read more

Pigweed at the two-leaf stage of growth which is the optimum stage for some post-emergent herbicides.

PHOTOS: Pest Patrol: Maximum weed stage where herbicides are still effective

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: < 1 minute A generation of glyphosate use has redefined what we mean by “apply herbicides to weeds that are small and actively growing.” Many interpret “small” to mean “about 15 cm” (six inches). If using “older” herbicides to manage glyphosate resistant weeds and your idea of small is 15 cm, then you may be disappointed with the […] Read more


The stage of lamb’s quarters when it is most susceptible to conventional herbicides. When lamb’s quarters is taller than 10 cm, control with glyphosate is reduced when applying at a rate of 0.67 l/ac. (540 g/l concentration). Increasing the rate to 1.34 l/ac. is needed to achieve adequate control.

Pest Patrol: Maximizing control of common lamb’s quarters

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Lamb’s quarters has consistently been identified as the most abundant and problematic weed affecting field crop production in Ontario even though the Pest Management Regulatory Agency database contains hundreds of herbicides that list lamb’s quarters as a susceptible weed. There is an arsenal of products available to farmers for the control of this weed, so […] Read more

A check strip on left where the Weed Zapper was not used — visible effects on weeds apparent on the right side.

Pest Patrol: Weed Zapper offers an alternative solution for killing weeds

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes One day during the summer of 2019, our future daughter-in-law came home one day pretty pumped about a new piece of farm equipment she had heard about. Shelby’s father’s farm has been in organic crop production for about 20 years now, and “some guy” was coming to try to zap the weeds in the soybeans. […] Read more


Farmers are looking for a solution to glyphosate-resistant Canada fleabane, which is a growing concern.

Can less be more when tackling herbicide resistance?

A coming formulation of glufosinate seeks to cut rates yet maintain efficacy

Reading Time: 4 minutes In the past five years, growers across Canada have been hearing more and more about a new weed control mantra. It’s called “doing only what’s necessary.” Weeds continue to challenge and frustrate in the field, of course, and there are always new issues like resistance in species such as Canada fleabane in the East or […] Read more

Waterhemp is now resistant to seven modes of action and is also showing signs of metabolic-based resistance.

New threat to weed management

Metabolic-based resistance is setting off alarms south of the border. There won’t be any easy answers

Reading Time: 6 minutes Here in the 2020s, herbicide resistance seems just part of the reality of managing weeds. It’s certainly not a new topic. We faced resistance to atrazine in the 1970s, then Group 2 ALS inhibitors in the 1990s and a more recent, widespread resistance to glyphosate. But of course the resistance threat keeps getting more complicated: […] Read more


Pest Patrol: Controlling weeds in non-GMO soybeans

Pest Patrol: Controlling weeds in non-GMO soybeans

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Weed control has always been a concern in non-GMO soybeans. Control of broadleaf weeds like lamb’s quarters and common ragweed has been inconsistent, and growers are always looking for ways to improve their results. General principles for weed control in non-GMO soybeans 1. Budget $80 to $85 per acre for weed control and plan for […] Read more

These thriving kochia plants are probably resistant to more than one herbicide mode of action.

Using a multi-prong strategy against herbicide resistant weeds

There are more pre-seed control options available to suppress herbicide-resistance, but use cultural management as well

Reading Time: 4 minutes More than half of western Canadian fields under annual crop production contain at least one herbicide-resistant biotype, according to surveys from 2014 to 2017. In Alberta, roughly 60 per cent of fields surveyed have resistant weeds; in Saskatchewan that figure is 57 per cent and in Manitoba it’s 68 per cent. “The surveys have been […] Read more