GFM Network News


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

Figure 3. Interveinal yellowing and browning typical of SDS infection.

Pest Patrol: Soybean cyst nematode (SCN) and sudden death syndrome (SDS)

#PestPatrol with Albert Tenuta, OMAFRA

Reading Time: 2 minutes The dry conditions in 2020 have been favourable for soybean cyst nematode (SCN) infection. A reminder that you can look for SCN by digging up plants with a shovel and gently removing soil and examining roots for the presence of the small white to yellow cysts (Figure 1 below). Cysts are considerably smaller (1 mm) […] 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


Figure 1. Attempted mixing of Dual II Magnum with ATS as the carrier (left) compared to successful mixing with water (right).

Pest Patrol: The importance of doing a ‘jar test’ with fertilizers and herbicides

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 4 minutes Each year I get more questions about mixing the liquid fertilizer, ammonium thiosulphate (ATS), with herbicides. With reductions in atmospheric sulphur deposits, Ontario research has shown positive yield responses in some crops when sulphur fertilizers are applied, so it makes sense that farmers are looking at ways to add sulphur to their crop in an […] Read more

Weed control with Authority Supreme (Groups 14 and 15), notice that overall weed control is good with the exception of Canada fleabane.

Pest Patrol: Weed control in IP soybeans

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes For more than a decade now, the University of Guelph and OMAFRA have been comparing the level of weed control, crop safety and grain yield associated with different herbicide programs in food grade, non-GMO soybeans, otherwise known as IP (identity preserved) soybeans. Table 1 (see below) summarizes the weed control and crop injury achieved with […] Read more


Figure 1: A weed seed’s perspective of having to germinate in the spring under a thick winter wheat canopy, which reduces the amount and quality of two key components for that weed to germinate: sunlight and heat.

Pest Patrol: Why growing cereals is bad for weeds

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 3 minutes The benefits of growing winter wheat in a crop rotation have been well established. Long-term research at the University of Guelph has shown a 10 bu./ac. increase in corn yields and a five bu./ac. increase in soybean yields when winter wheat is grown. Other benefits, such as increased soil organic matter when cereals are grown, […] Read more

A field sample of wild oat screened with three chemical families within the Group 1 mode of action by the Tardif lab. Note there is resistance observed when Puma (a “fop”) was applied, moderate resistance when Achieve (a “dim”) was applied and moderate susceptibility when Axial (a “den”) was applied.

Pest Patrol: Herbicide-resistant wild oats in spring cereals

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 4 minutes Q. Are there any solutions to control herbicide resistant wild oats in spring cereals? A. Wild oats have been an undesirable weed in spring cereal crops for many years, and its control has been limited to a handful of herbicides within the same mode of action (specifically, WSSA herbicide Group 1). Until recently, there have […] Read more


Figure 1. The white fluffy growth on Canada fleabane rosettes following several weeks in the cool and wet environment of the vernalization chamber.

Pest Patrol: White mould and Canada fleabane

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes I could barely contain my excitement. What was this fluffy white stuff that had taken down large fleabane rosettes? Had I accidentally stumbled upon an effective biocontrol option for glyphosate-resistant Canada fleabane? I wondered, what would it take to reproduce this potent material so we could inoculate plants throughout Ontario? I quickly took a sample […] Read more

What can potato chips teach you about weed control? You might be surprised.

Pest Patrol: Dealing with bias in pest management research trials

#PestPatrol with Mike Cowbrough, OMAFRA

Reading Time: 2 minutes I have biases. Perhaps that’s a surprising statement coming from someone who is supposed to be impartial, but experiences lead to biases. It’s human nature. The bigger question is how does one account for and neutralize those biases when evaluating something such as a weed control program? That’s the topic that I wanted to tackle […] Read more