Biology is forever adapting — to tillage, to cropping systems, and to selection pressure of herbicide applications.
The advent of herbicide resistance has created a huge challenge for farmers across North America. Some of the worst weeds include kochia, fleabane, wild oats, waterhemp, and Palmer amaranth.
Managing these weeds and delaying more resistance requires a thorough plan, and to help build the plan, we go to Rob Bahry of ADAMA Canada and Marc Maisonneuve of Corteva Agriscience, on this episode of The Agronomists.
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- Integrated approach. There are many factors that impact herbicide performance
- There is 19 different herbicide groups listed in Manitoba. Let’s not use the same mode of action over and over.
- Kochia is a focus in the west, because of how it is so resistant
- How do weeds become resistant? Overuse, lack of changing what we are using, lack of crop rotation, plus the weeds themselves
- Two types of resistance: metabolic resistance and target site resistance
- There are lower risk of resistance products, but all products are at risk for resistance to some level
- Why are some weeds more prominent to resistance than others?
- It doesn’t have to be consecutive applications to start developing resistance
- Let’s say it a little louder for the ones in the back: tank mix!
- The problem can just get worse and worse and worse…plan ahead, if you can
- It’s a numbers game. Depends on how many seeds the weed happens to have can speed up the process
- No-till and chem fallow — has this accelerated herbicide resistance? In short — yes. Especially when it comes to glyphosate
- Is there still a time and place for just glyphosate alone? If we can help it…no
- When we adapt our strategies, the plants just adapt as well
- Herbicide layering. If you haven’t looked into it, you should
- Understanding the weeds you are up against and how the seeds spread is key, too
- Goats or sheep will eat these weeds! Ruminants for the win? (Depends who you are talking to)
- Weeds will always find a way…
- Mowing and managing a weeds spread can be helpful, too
- You have to catch these weeds before they go to seed
- To detect herbicide resistance, the first step is to of course scout
- Rotating buys you time; mixing buys you shots
- The management piece is really important when it comes to weed control. Integrated pest management
- We can’t spray our way out of resistance
- If we are to take glyphosate out of the mix entirely, it complicates things in a big way
- Glyphosate takes the place of tillage in a lot of places…by removing glyphosate, it could bring back more tillage