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

Quinoa planted into a stale seedbed and with the use of an experimental herbicide (left) compared to the same herbicide applied but without the use of a stale seedbed (right).

Pest Patrol: Try the stale seedbed approach for weeds in alternative crops

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Q: I’m looking to grow a new crop where there are few herbicides available to control weeds. Are there any non-chemical methods to reduce the number of weeds that could emerge in the crop? A: Since I began with OMAFRA in 2002, I’ve been involved in projects that investigated methods to control weeds in “new” […] Read more


Canada fleabane seedlings that will be treated with glycine and glyphosate combinations in a growth chamber environment.

Pest Patrol: The continuing fight against glyphosate-resistant Canada fleabane

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Glyphosate-resistant Canada fleabane is found in 30 counties across Ontario and can cause yield losses exceeding 50 per cent in both corn and soybeans. Since there are only a few other herbicides that are effective at controlling it, this glyphosate-resistant weed has been one of the most troublesome weeds in Ontario. So, what if you […] Read more

Figure 1. An overhead look at the level of control that cereal rye has provided when it was seeded the previous fall (mid- November) at 60 lbs./ac. (left) compared to no cereal rye planted (right).

PHOTOS: Pest Patrol: Cover crops versus glyphosate-resistant weeds

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: < 1 minute Q: Can cover crops be an effective tool to manage glyphosate-resistant weeds? A: My colleague Dr. Clarence Swanton (University of Guelph) used to say that based on research he did in the 1980s, one should not expect to control weeds with cover crops. Their utility was in preventing soil erosion and improving soil health but […] Read more