Watch for these weedy invaders in Ontario


You’ve probably seen and heard reports of the impact invasive weeds like waterhemp and palmer amaranth could have on Ontario crops.

While these two heavyweights tend to capture the headlines, there’s a host of other invaders also looking to find a home in your fields.

At the recent Southwest Crop Diagnostic Day, Ridgetown College, University of Guelph weed technician Dave Bilyea provided a snapshot of waterhemp and other problematic weeds that are present in Ontario, but often go undetected.

Rough stalked bluegrass is often mistaken for quackgrass. Photo: Dave Bilyea

In this video, Bilyea gets up close with waterhemp, which looks very similar to red root and green pigweed. In Ontario, waterhemp plants have been found to be resistant to Group 9, 2 and 5 herbicides and all Ontario row crops could be at risk as resistant populations spread, he notes.

Farmers should also keep an eye out for invading grasses. Rough stalked bluegrass is often mistaken for quackgrass and can be very competitive with other small grains. Annual bluegrass, similar to Kentucky bluegrass, is another invader that can cause headaches in cereal and row crops, Bilyea explains.

Wild parsnip, similar to wild carrot, can invade forage and grain fields, reducing quality and saleability. The plant’s sap can also produce nasty burns like giant hogweed. It’s classified as a noxious weed in Ontario.

Scouring rush is another weed on Bilyea’s radar. It’s a leafless, green bamboo-like plant with stems that can grow up to five feet tall. Generally, it’s been found around the perimeter of fields, but it has been migrating into row crops such as soybeans.

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