BRANDON, Man. (Staff) – Cut them. Spray them. Mow them down. Rotate them out.
“Use anything you want. You can even use napalm, I don’t care,” said Luc Bourgeois, a weed specialist at the University of Manitoba.
Bourgeois emphatically told farmers they must take action against wild oats resistant to Group 1 herbicides at an annual zero-till conference held here last week.
Bourgeois is completing a study on these rogue weeds that shows they’re not as rare as farmers and chemical companies apparently hope.
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He used Manitoba Crop Insurance Corporation data to determine which townships and areas of the province are at risk for the weeds because of continuous use of Group 1 herbicides.
Then, he sampled 30 fields in one high-risk area near Treherne in south-central Manitoba to see if he could find any of the weeds. Most of the fields had been treated with Group 1 herbicides almost every year since 1984.
Bourgeois said Group 1 herbicides, such as Hoe-Grass, Poast and Puma, are popular because they are easy to mix, can be used on any crop and have traditionally been efficient in killing wild oats.
Surprising finds
He thought he might be able to find two or three resistant plants in the study, even though the farmers had not noticed a problem. Bourgeois was surprised to find so far, 21 fields out of 30 have a problem. Results from five fields are still being evaluated.
Only four fields did not have resistant wild oats – but one of these had resistant green foxtail.
Statistics from the study show farmers who have used Group 1 herbicides for eight of the past 11 years will have resistant weeds. And fields with many large patches of wild oats stand a greater chance of having some that are resistant.
Bourgeois said most farmers will be able to use Group 1 herbicides every four or five years on infected fields, if they mow patches of wild oats before they seed and apply a variety of products to the patches.
