Strong Weed Management Key in Nebraska

By Scout Nelson

Herbicide-resistant weeds are becoming a serious concern for Nebraska agriculture, affecting crops from corn and soybeans in the east to sugar beet in the Panhandle. These weeds are reducing herbicide effectiveness and increasing production costs.

In Nebraska and the Midwest, resistant species such as Palmer amaranth, waterhemp, kochia, marestail, and ragweed is common. Many now resist multiple herbicide groups, including atrazine, glyphosate, PPO inhibitors, and ALS inhibitors. Some Palmer amaranth and waterhemp populations can survive five or more herbicide groups, leaving limited chemical control options.

Overuse of the same herbicides, particularly glyphosate, has accelerated resistance development. Six glyphosate-resistant weed species are confirmed in Nebraska. Multiple herbicide-resistant weeds further limit control methods, making reliance on chemical control alone unsustainable.

Stacked herbicide traits, like dicamba and glufosinate resistance, can provide short-term benefits but may also lead to new resistance if not combined with other control methods. This makes integrated weed management (IWM) essential.

Key IWM strategies include rotating herbicide modes of action, using overlapping residuals, rotating crops and traits, planting cover crops, increasing crop competitiveness, and using mechanical control when needed. Frequent scouting, tailoring approaches to specific weed species, cleaning equipment between fields, and consulting with experts are also critical.

Palmer amaranth is a particular threat, growing about two inches per day and producing vast seed quantities if uncontrolled early. Even small populations can create significant future infestations.

Looking ahead, experts warn that herbicide development is slowing while resistance is increasing. This makes a systems-based approach to weed control vital for long-term crop production.

Herbicide resistance is not just a chemical problem, it's an agroecological challenge that requires a system-level response. By adopting diverse and integrated weed control methods, Nebraska can protect crop productivity and sustainability.

Photo Credit:united-soybean-board