Herbicide Layering
Herbicide layering involves using two or four herbicides, with different modes of action in sequence during a growing season. The strategy delivers a one-two punch for better control, especially of problem weeds that may not be as susceptible to a single herbicide application. Wild oats and cleavers are examples of tough-to-control weeds.
A tank mix scenario or other program that might include a faster acting contact herbicide with a residual product is a good approach. The first product weakens the weed, while the second follows up with effective control.
Developing a good herbicide rotation over subsequent seasons is important to reduce the risk of selecting weeds that show herbicide tolerance. But the now commonly-recommended layering approach, with multiple modes of action in the same weed control season, and then rotating chemistries through the crop rotation, can be even more effective in the battle against herbicide resistance.
- Start with a proper pre-seeding burndown to control the first weed flush and reduce weed numbers.
- Follow that up with a tank mix or combination of at least three to four different products (the more the better) with different modes of action and residual activity for effective control.
- It's an effective strategy for catching herbicide resistant weeds you may not be aware of, and/or preventing the resistant ones from getting a start.