Since the 1980s, wild oats have been recognized as one of the most harmful weeds in western Canada. Like any weed, wild oats compete with crops for light, water and nutrients. Left alone, at just 10 wild oat plants per square metre, this pest can lead to yield losses of up to 10 percent in canola, for example.
But the bigger problem is that because of its broad genetic diversity and prolific seed production, wild oats are highly susceptible to developing herbicide resistance. Many farmers are already seeing Group 1 and 2 resistant wild oats in their fields. And since left unabated, these seeds can sit in the seedbank for up to 7 years, this can make for a long term, recurring profitability issue.
So, what can be done to slow the spread of herbicide resistant wild oats?
Here are three ways to protect your crop from resistant wild oats.1. Plan your spring burnoff
Don’t rely on a fall burn off to take care of your spring weeds. Time your pre-plant burnoff as close to seeding as possible. This will help make sure your crop has a head start once the next round of wild oats is ready to emerge, reducing competition and limiting possible yield losses.2. Come at it from all (herbicide) angles
While wild oats have exhibited multiple resistances, it’s unlikely that any one individual weed will show resistance to more than one mode of action. So, as you get ready to spray throughout the season, make sure you’re reducing selection pressure by using a variety of herbicide groups in your mix. Always read and follow the label directions to ensure you’re getting the most out of every application.3. Rotation, rotation, rotation
If your weeds always know what’s coming, it’s easy for them to adapt. Crop rotation not only gives weeds new plants to compete with, it also gives you more herbicide options to use against them year over year. Herbicide-tolerant crops provide a wider variety of in-season control options—broadleaf crops can utilize different modes of action than grass crops, and variety allows you to save your Group 1 and 2 options for when you need them most.
While it’s tempting to simply rotate between one or two more profitable crops, looking towards the extended goal of stopping herbicide resistance on your farm to provide more long-term profitability may be a better plan.