GFM Network News


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: Annual bluegrass.

Pest Patrol: Bluegrass becomes an emerging problem in field crops

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 4 minutes In Ontario, turf-like grassy weeds are being found in more cultivated fields. In herbicide-tolerant corn and soybean, control with glyphosate has been inconsistent. In cereal and forage crops, fast growth of these grasses in the spring makes them too big to be controlled with herbicides. Let’s review what is being found in fields and how […] Read more


Soybean planting showing leaf injury symptoms caused by a “bleaching” herbicide.

Pest Patrol: Crop injury from herbicide residues more common in 2020

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 4 minutes In 2020, a few farmers observed leaf injury in their soybean crops. The injury caused parts of the leaf to turn white, then yellow (see photo at top). This injury is typically caused by “bleaching” herbicides. It was odd, though, because the bleaching herbicide had been applied to the previous year’s corn crop, and it […] Read more

RWOAC chair Eric Johnson wants to work with farmers to find out their ideas for managing resistant wild oats.

A new plan of attack for resistant wild oats

With more wild oats showing resistance to Group 8 herbicides, this action committee is going on the offence

Reading Time: 5 minutes In the 1970s, the Wild Oat Action Committee was formed to encourage farmers to control the pesky weed, especially with herbicides. Now a new version is back, but with an ironic twist — the herbicides aren’t working. A recent Prairie-wide study reveals 69 per cent of tested wild oats proved resistant to some modes of […] Read more


Figure 1 (left). These are the most often mentioned “challenging to control” weed species. In order from most common to least common: lamb’s quarters, Canada fleabane, foxtails, pigweed, common ragweed, giant ragweed, wild carrot, waterhemp, sow-thistle, velvetleaf, fall panicum, wild oats, vetch and bluegrass. Figure 2 (right). Management practices identified by agronomists that improved on-farm weed control. Management practices are ranked beginning with most often mentioned: fall weed control, residual herbicides, multiple modes of action, crop rotation, soil fertility, cover crops, scouting and two-pass herbicide applications.

Pest Patrol: Control of income-robbing weeds

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes All farmers know that poor weed control reduces income. Staying on top of income-robbing weeds requires two things: first, knowing which species cause farmers the most grief and, second, understanding which management practices consistently provide good weed control. I asked over 30 agronomists from across Ontario to share their biggest challenges and successes in weed […] Read more

Figure 1. Dog strangling vine along a roadside in York Region where it is creeping into the fenceline and bordering corn field.

Pest Patrol: Dog strangling vine control with herbicides

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes An invasive perennial weed from the milkweed family, dog strangling vine is extremely difficult to control once it gets established (Figure 1 at top). Progress has been made on biological control of this weed in Ontario through the release of Hypena opulenta, a leaf-feeding caterpillar. However, integrated strategies that include both biological and chemical methods […] Read more


A sight no one wants to see in soybeans: cupping of the leaves caused by dicamba.

U.S. legal system helps weeds win

Luckily, Canadian producers are still outside the reach of the Ninth Circuit Court ruling on dicamba-based herbicides

Reading Time: 5 minutes In farming circles, the term “less-forgiving” has become more than a cliché. It’s now a mirror on reality. Farmers are already dealing with an incredible list of challenges and complexities, including everything from new seed technologies, concerns about land costs, equipment decisions, commodity markets, trade issues… you name it. Now growers in the U.S. must […] Read more

Keeping the corn plant weed and stress free early allows the plant to form a larger cob, up to its genetic potential.

Focus on the ear leaf in corn production

Keeping the corn plant weed and stress free early allows the plant to form a larger cob, up to its genetic potential

Reading Time: 6 minutes It seems every growing season brings something new for growers to manage. Sometimes it’s a new disease or its anticipated arrival. Other years, it’s learning to cope with the impact of weather conditions, or a sudden weed flare-up. It’s a testament to modern agricultural science that the more we learn, the more questions we ask. […] Read more


Waterhemp towers above a soybean canopy.

Pest Patrol: How accurate are plant identification apps when it comes to weeds?

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes Recommendations for plant identification apps were recently making the rounds on social media. Of course it would be nice to accurately identify an unknown weed in your field by taking a picture instead of sending it to an “expert” or a diagnostic lab. However, many of the top-rated plant identification apps are not particularly accurate […] Read more

Figure 1: The untreated control plot.

Pest Patrol: The latest word on nipplewort in cereals

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes Here’s a question in my in-box. “I have a customer with a no-till rotation that has nipplewort — a lot of it. We found some pretty decent options for most crops in the rotation to clean it up before planting, but he’s got some in his wheat this year too. “What would be our best […] Read more