Controlling Palmer Amaranth with Metribuzin Tolerant Soybean Varieties

Dr. Jason Norsworthy says that metribuzin is an extremely important component of weed control programs, especially when controlling PPO-resistant and ALS-resistant Palmer amaranth. Researchers have found that using metribuzin in combination with other herbicides can be most effective for extended residual weed control.

As one of the most common weeds in Arkansas as well as the top weed in the United States, researchers have screened germplasm for over the past decade to learn how to control Palmer amaranth. New technology has allowed for a new soybean, LibertyLink GT27, to emerge. The GT27 soybean can be treated with HPPD herbicides like isoxaflutole, which is also used in corn. Metribuzin has a similar mode of action as atrazine in corn and can be used to extend residual weed control with the GT27 soybean, especially when mixed with isoxaflutole.

Norsworthy recommends that growers select a soybean variety with metribuzin tolerance. He also recommends starting with metribuzin in a weed control program and using a combination of other compatible herbicides for the most effective weed control over an extended period of time. Researchers will continue to screen germplasms to make sure that Arkansas growers are making an informed decision when selecting a soybean variety.

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