GFM Network News


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

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


Canada fleabane rosette during October.

Pest Patrol: Management practices that controlled glyphosate-resistant weeds in 2020

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Several Ontario agronomists recently shared their most successful strategies for managing glyphosate-resistant weeds. Four general strategies were identified: 1. Inclusion of winter wheat in the crop rotation By early spring, winter wheat’s dense ground cover does not provide a good environment for annual weeds, like waterhemp, to germinate. There are also many herbicides that are […] Read more

Figure 1. Canada fleabane leaf injury caused by 28 per cent UAN.

Pest Patrol: Using 28 per cent to manage Canada fleabane

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes I’m thankful that farmers and agronomists share their ideas, experiences and questions with me as it relates to killing weeds. During the winter months I’ll test out ideas in the greenhouse to see if they’re worth taking to the field. I’m fortunate that we have some great public-sector researchers (such as Dr. Page, Dr. Sikkema […] Read more


Figure 4: Waterhemp in soybean.

Pest Patrol: Dealing with waterhemp and Canada fleabane

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes In last month’s #PestPatrol, we discussed options for the control of glyphosate-resistant waterhemp. However, across the province, there appears to be a more immediate threat for the 2020 season from glyphosate-resistant Canada fleabane. This article will focus on management strategies to control both species at the same time. It is true that glyphosate-resistant Canada fleabane […] Read more

Trying to overcome Canada fleabane via breeding is the target of many researchers and breeders.

Better herbicide tolerance

Better technologies are coming, but we’ll need patience and shrewd management until they arrive

Reading Time: 4 minutes Count off the many challenges facing a farmer in any growing season and outside of weather conditions, the biggest impediment has to be weed management, particularly as it relates to herbicide tolerance. In spite of the importance of varietal or hybrid selection and fertility, and the potential for yield losses from insect pests and diseases, […] Read more


Pre-plant applications of dicamba at the high rate and to emerged fleabane rosettes have provided the most effective control of glyphosate-resistant Canada fleabane (left) compared to an unsprayed strip (right) when planting Xtend soybean varieties. A followup, post-emergence application of dicamba may be necessary when new seedlings have germinated following crop emergence.

Pest Patrol: Control of Canada fleabane

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Q: Canada fleabane has shown up in various places on our farm this year. I assume it is glyphosate resistant. Do I have any other options for soybeans other than Xtend beans? A: Yes, research conducted by the University of Guelph (Ridgetown Campus) has shown that the addition of Eragon LQ (30 ml/acre) + Sencor […] Read more

Figure 1. Canada fleabane plants the following spring after surviving fall tillage. Note the plants have multiple branches at the base and were often 10 to15 cm taller than plants not exposed to fall tillage.

Pest Patrol: What have we learned in 2017 for managing glyphosate-resistant Canada fleabane?

#PestPatrol with Mike Cowbrough, OMAFRA, Dr. Clarence Swanton, Dr. François Tardif and Peter Smith, University of Guelph

Reading Time: 2 minutes Multiple strategies are needed to control glyphosate-resistant Canada fleabane. Experience has taught agronomists and farmers that simply tank mixing another mode of action won’t be a good enough long-term approach. Since 2016, we have evaluated different management tactics for Canada fleabane. The following are the results at our Oxford and Norfolk county field locations. Tillage […] Read more


Managing for glyphosate-resistant Canada fleabane — and other weeds — is possible, but it will cost farmers more.

Tough news on fleabane

It takes a well thought out plan to keep glyphosate-resistant Canada fleabane in check

Reading Time: 6 minutes The world of science can often provide insight into some rather grim realities. But sometimes, fortunately, it can provide more than just insight. It can provide strategic help too. That’s the case with Dr. Peter Sikkema, who opened 2017 by making a presentation on herbicide-resistant weeds at the two-day Southwest Agricultural Conference (SWAC) at the […] Read more

corn crop with fungicide resistance

On the sidelines

Disease resistance isn’t a big corn or soybean issue today, but...

Reading Time: 6 minutes With so many stories about resistance hitting the farm news in the last five years, any new stories about chemical resistance on the farm now tend to generate one of two reactions: disinterest (approaching boredom) or a touch of hypersensitivity. Neither is the best reaction, especially with all the new learnings about the possibilities of […] Read more