Today’s the day to manage herbicide resistance on your farm

Category: Grow Grain

Herbicide resistance is a growing threat. Here’s why we need to take a close look at the issue right now.

We’ve all had herbicide resistance on our minds for a long time. The first documented resistant weeds in western Canada showed up in the 1980s. So  why should you do something about it now? Because resistance has grown to a magnitude that we just can’t ignore.

Recent surveys suggest that 41% of prairie fields have Group 1 resistant wild oats. That’s a huge number. With kochia, we just presume 100% of kochia is resistant to Group 2s. And if a weed is resistant to three modes of action (like Group 1, 2 and 8 resistant wild oats) it doesn’t leave us many herbicide options.

Economics tend to influence producers to push their rotations, even though a three- or four-year rotation with cereals, oilseeds and pulse crops in the mix is one of the best ways to delay weed resistance. Tank-mixing is another.

How important is glyphosate?

When you look at the number of times glyphosate shows up in a herbicide rotation, and how important effective control with glyphosate is, you don’t want to lose it.

We rely on glyphosate for a range of options, including the reduction of tillage. Adding iron back into the rotation to control weeds is not something we want to do any time soon. 

Using glyphosate on its own, especially for pre-seed burnoffs, creates real risk. It’s such an easy opportunity to tank-mix pre-seed, with so many effective options. If you wait until you have an issue, by that time, it’s too late.

Weeds constantly evolve

Weed researchers like Eric Johnson, a research associate with the Weed Control Research Program at the University of Saskatchewan, say it’s not just about herbicides – weeds constantly evolve. Johnson says hand weeding barnyard grass in rice used to be easy in the Philippines – the barnyard grass looked different than the rice. But over 100 years, the grass evolved so it looks identical to rice and they can’t hand pick it anymore. 

How we farm today can prolong the efficacy of our herbicide and delay the development of resistance. As a producer, you need to use all the weed management tools at your disposal – chemistry, agronomy, seeding dates, crop rotations, cropping systems – to keep the weeds off balance and deal with that evolution.

Learn from our neighbours

We can learn from our U.S. and Australian neighbours. With similar issues and problems, we can see first-hand how bad weed resistance can get. In some cases, farmers are reintroducing tillage because the herbicides available don’t work anymore. That jeopardizes all the soil benefits that direct seeding and min-till provide. 

Our crop rotations tend to be more diverse than the corn-soybean U.S. rotation or the cereal-on-cereal Australian rotation. But that might mean we’re just delaying the inevitable if we don’t take control of herbicide resistance now. 

Why now? We have a “crystal ball” opportunity – we can see what’s happening to them. If we don’t take action, we could be next.

Agronomist in the mix

Working with a Cargill agronomist helps farmers chart their course for weed resistance management. As agronomists, we love dealing with chemical weed control and everything that revolves around that. But we also love the cultural parts of agriculture – seeding rates and dates, variety selection, rotations – stuff we spend time studying, researching and applying to specific farm situations. 

We don’t use a one-size-fits-all formula. Our team will work with you to find a solution that fits your situation at the farm level. We’ll look at your overall herbicide rotation to find opportunities to control resistant weeds and slow their development. 

Like so many other systems you use each day, it pays to take a proactive approach. This is your chance to create a sustainable resistance-management plan for your farm. Start planning with an expert today. 

Use our online form to book a free one-hour consultation with an agronomist in your area. You can also visit our Herbicide Resistance Resource Centre to learn more.

Tags: Agronomy, Crop Protection, Herbicide, Weed Management, Herbicide Resistance

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