Setting Up Crops for Success Against Weed Resistance
April 1, 2025 According to the International Herbicide Resistant Weed Database, around the globe, there are 534 unique cases of herbicide-resistant weeds comprising 273 species. In addition, weeds have developed resistance to 21 of the 31 known herbicide sites of action and to 168 different herbicides. Herbicide resistant weeds have been reported in 101 crops in 75 countries. (For more on the state of weeds, look for Eric Sfiligoj’s article in the April issue of CropLife Magazine).
One way to combat resistance is to control weeds before they emerge and need to be sprayed.
In other words, preventing them: “is important to slow herbicide resistance by using a robust pre-(emergent), because that will reduce selection pressure by reducing the number of individual weeds that a given post emergent knockdown herbicide like Liberty ULTRA needs to control,” says Liam Vincent, Technical Marketing Manager, BASF.
To that end, Zidua PRO is comprised of three existing BASF herbicides: Sharpen (active ingredient – saflufenacil), Pursuit (active ingredient – imazethapyr), and Zidua (active ingredient – pyroxasulfone) which as a convenient premix product offers fast knockdown and long-lasting residual of tough to control weeds like waterhemp and palmer amaranth.
The Sharpen (saflufenacil) component brings three to five times faster burndown compared to 2,4-D or glyphosate, with excellent activity on weeds like marestail which often emerge and are problematic when soybeans are planted. Pursuit offers superb large-seeded broadleaf and grass control while the Zidua component provides small-seeded broadleaf weed control, the company says.
“Having three modes of action that work collaboratively, to control many different types of weed species, is critical to setting crops up for a strong start,” Vincent says. “All of them really fit well together on that soybean acre and lend themselves to flexibility for the farmer as Zidua PRO can confidently be used across all soybean trait platforms and in any tillage system.”
For herbicides to achieve their goal, consultants, retailers and end-users need to work with the products to ensure they’re being used properly.
“We need to have a mindset shift about weed control and commit to putting as much upfront as you can to protect your crops, and ultimately, by having multiple modes of action, you’re preventing weed species from emerging,” Vincent says. “If we can reduce the number of weeds that are emerging (and need) to be sprayed by our post herbicide, we can help reduce selection pressure.”
While starting with a strong pre-application is important, spraying a post-application will be needed much of the time. BASF works with and educates retailers so they can in turn ensure their grower-customers apply products properly. The company urges growers to follow the START rules to optimize their Liberty ULTRA applications.
START
- Size – Spray small weeds (less than 3 inches)
- Timing – We want people to be spraying during banker’s hours to avoid issues with efficacy. Make applications 2 hours after dawn and 2 hours before sunset.
- AMS – Ammonium sulfate – Is critical for driving the mode of action for glufosinate.
- Residuals – We know glufosinate is a point-in-time herbicide. There’s no residual control that comes from it. So, include residual herbicides to hold back additional weed flushes
- Twenty and Tips – Twenty gallons per acre to get effective coverage and to use tips that will help deliver medium coarse droplets.
To learn more about Zidua PRO and the full portfolio of BASF innovative weed control solutions, visit agriculture.basf.us.
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