Resistant weed testing results – 2025 season
Herbicide‑Resistant Weed Testing Results (2025) See the latest results for herbicide‑resistant weed testing in Ontario, including distribution maps and resistance summaries. Read the Full Article […]
Category: Weeds
Which residual corn herbicides allow cover crops to be inter-seeded?
With a narrow window to establish cover crops after corn harvest, some farmers have experimented with inter-seeding cover crops when corn is at the 6-8 leaf stage. However, the sensitivity of different cover crops to residual corn herbicides is unknown and could negatively affect their establishment. A multi-year study looked at the sensitivity of six […]
Purple deadnettle control in winter wheat
Q: I’m seeing more henbit and/or purple deadnettle in my winter wheat crop? Should it be controlled and what can be done to control it? A: Both henbit and purple deadnettle are two weeds often discussed inter-changeably because they look similar, are from the same genus (Lamium) and have similar emergence patterns (mainly in the […]
Palmer amaranth found in Ontario
It was only a matter of time before Palmer amaranth was found on a farm in Ontario. Although technically it was found back in 2007 along a rail line outside of Niagara Falls, surveillance of that area in the years following have never detected any plants since the initial finding. In late summer, an individual […]
How to Make Annual Ryegrass Easier to Kill
Co-authored by Mike Cowbrough, OMAFRA Weed Management Specialist – Field Crops An annual ryegrass cover crop is excellent at scavenging nitrogen, improving soil structure, and preventing erosion. It tolerates low light levels well enough to be inter-seeded into an established corn crop and grows quickly enough with adequate moisture to help suppress weeds. For ruminant […]
Tank mixing urease and nitrification inhibitors in corn weed-and-feed applications
This article is based on work performed by Mike Schryver, BASF Technical Service Specialist. It was originally published at Sprayers101.com, and you may have been redirected here from that site. Introduction Nitrogen is an essential nutrient required throughout a plant’s lifecycle. It is commonly applied to corn in either a granular form as urea or […]
The Crop Protection Hub -How does it work?
All of OMAFRA’s pest management publications have been digitized into the Crop Protection Hub. While we have received positive feedback on this tool, we do understand that some prefer the print publications. We are working on a print solution from the Crop Protection Hub that we hope meets those needs. If you would like to […]
How do I control bluegrass in winter wheat?
Bluegrass competition in winter wheat can result in yield losses of up to 50%. We reviewed current research to provide recommendations for reliable control of annual and roughstalk bluegrass in Ontario. […]
Optimizing the performance of glyphosate in field crops
Reduced supply and increased costs of glyphosate have prompted many to reevaluate how they use this herbicide. The following three questions are most common: […]
Phragmites control with herbicides and biological agents
This post provides an overview of the research that has been done in Ontario to evaluate the control of phragmites with herbicides. […]
Dog Strangling Vine Control with Herbicides
An invasive perennial weed from the milkweed family, dog strangling vine, is extremely difficult to control once it gets established (Figure 1). 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 […]
Ontario Weed Committee
Pre-Harvest Herbicide Timing in Soybeans
A pre-harvest herbicide treatment can make harvest more efficient when there are an unacceptable number of weeds in a soybean crop. Both conventional and glyphosate tolerant fields that are weedy can benefit from a pre-harvest herbicide. Drier plant matter will pass more easily through the combine, lowering seed losses and reducing seed staining… […]
Waterhemp: biology and control
This post will serve as a repository for all information associated with the management and control of waterhemp in Ontario. […]
Mixing “ATS” with herbicides: The importance of a “jar test”
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 and so it makes sense that farmers are looking at ways to add Sulphur to their crop in […]