GFM Network News


Contrast in control of Roundup Ready alfalfa with herbicides applied in early fall (foreground) compared to late fall (background).

Pest Patrol: Killing off Roundup Ready alfalfa

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Six tank-mix partners are recommended for the removal of Roundup Ready alfalfa, and since they vary significantly in cost (Table 1 below), their effectiveness was evaluated in a trial conducted at the Elora Research Station in 2018-19. Growing degree day accumulation after herbicide application appeared to have the greatest effect on the control of Roundup […] Read more

Figure 1: Purple deadnettle in a wheat field — October 2018 at a yield-reducing population density of around 500 plants per square metre.

PHOTOS: Pest Patrol: Purple deadnettle and henbit control in winter wheat

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Q: I’m seeing more henbit and/or purple deadnettle in my winter wheat crop. Should it be controlled, and how? A: Henbit and purple deadnettle are often discussed interchangeably because they look similar, are from the same genus (Lamium) and have similar emergence patterns (mainly in the fall, but henbit will also emerge in spring). Both […] Read more


A cereal rye cover crop established after corn silage in the fall of 2018.

Pest Patrol: Planning for cover crops

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Q: I want to plant cover crops after harvest. Should I be concerned about any herbicide residues that would make it harder to get them established? A: Two important factors influence the potential for herbicide carryover that could negatively affect establishment of a desired cover crop: The sensitivity of the cover crop to herbicide residues. […] Read more

Volunteer corn.

Pest Patrol: Manage volunteer corn in your 2019 soybeans

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Q: Due to a challenging 2018 corn harvest, I’ll likely be looking at more volunteer corn in my 2019 soybean crop. What suggestions do you have for managing this weed? A: The only option to control volunteer corn in soybeans is to use one of the post-emergence herbicides from the Group 1 mode of action. […] Read more


Dr. Clarence Swanton.

Pest Patrol: Thank you, Dr. Clarence Swanton

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes “Matty Cowlick” is indifferent to the recent retirement of Dr. Clarence Swanton, weed scientist in the department of plant agriculture at the University of Guelph. But I’m happy for him. I’m happy that Clarence will continue with his research program and to advise graduate students, and happy that he will have more time to spend […] Read more

Figure 4.

Pest Patrol: Use your phone to capture and document pest activity

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes “If you want to have the upper hand on weeds, you need to know every little detail about their existence.” The above quote is straight from the great Jack Alex, retired botany professor and herbarium curator at the Ontario Agriculture College, who used to repeat it to me at every opportunity. Fortunately, most of us […] Read more


Drought stress symptoms in corn leaves where no soil-applied herbicides had been applied and weed control was done with a late post-emergence application.

Pest Patrol: Don’t be cheap with weed control

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes “Weed control is an investment into the current and future crops on every field.” The above quote was parting advice from Norfolk and Oxford County farmer Ann Vermeersch at the 2019 FarmSmart Conference in Guelph. In front of 80 farmers and agronomists, I moderated a session with Vermeersch and Steph Kowalski, a certified crop advisor […] Read more

Figure 4: A close up of foliar leaf burn from ATS and herbicide applications in 2018.

Pest Patrol: Questions about sulphur deficiency

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes I’m asked if growers can mix ammonium thiosulphate (ATS) with herbicides and fungicides to address sulphur deficiency symptoms, or should they apply it separately with streamer nozzles? With reductions in atmospheric sulphur deposits, Ontario research has found significant sulphur responses (10-14 bu./ac.) on some fields, while others have shown little or no response, especially where […] Read more


A seedling adzuki bean plant.

Pest Patrol: Managing volunteer adzuki beans

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Q: Has any work been done with controlling adzuki beans in IP, non-GMO soybeans? A: Chris Kramer and colleagues at the University of Guelph evaluated management of volunteer adzuki beans (photo at top) during a period of four seasons. The main challenge with adzuki beans is that their pods shatter easily and their seed coat […] Read more

Figure 1: This unsprayed control treatment consists mainly of common ragweed but with green foxtail, common lamb’s-quarters, witchgrass, crabgrass and red-root and green pigweed.

Pest Patrol: Weed control in identity-preserved, non-GMO soybeans

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes A decade of public research trials evaluating weed control in non-GMO soybeans at the University of Guelph has demonstrated that the key to success is to start with a soil-applied herbicide program that has three or more different modes of action. In Ontario, there are a number of common weeds (e.g. common ragweed, lamb’s-quarters, foxtail […] Read more