Herbicide-resistant weeds have been a problem in Canada for years, and the problem continues to escalate. As of 2018, there were 76 unique weed biotypes across Canada with herbicide resistance (HR), according to Hugh Beckie. In Ontario alone, there are 35 unique HR weeds.
Adam Pfeffer, with Bayer Crop Science, has some advice for those dealing with three of the most difficult weeds. Read more on that here.