By FMC

Control of yield-robbing weeds has become increasingly difficult, emphasizing the need for a multi-pronged approach. Even with the best preemergence or postemergent herbicide application, many weeds like waterhemp and pigweed continue to germinate throughout the entire growing season. These driver weeds grow at rapid rates and produce large amounts of weed seed that can persist in the soil for years to come.

With their robust reproduction characteristics and extended germination period, driver weeds are difficult to consistently control. Their staggering seed production multiplied by even a few escapes means newly planted soybeans are quickly outnumbered and outcompeted for moisture and nutrients.

Without effective weed management that reduces the soil seedbank, risk for resistance will continue to develop, creating a hard-to-stop cycle. The move to help end this vicious cycle: overlapping residual herbicides.

Mitigating weeds, helping enhance yields

Overlapping residual herbicide programs are designed to help preserve yield potential by reducing or eliminating weed competition from the start. This strategy consists of multiple herbicide applications with residual chemistries applied in a timely manner to recharge residual protection before the previously applied herbicide loses efficacy.

Overlapping residual products help prevent a lapse in coverage, preventing competition for essential plant growth resources. The use of multiple modes of action contributes to the reduction of resistance development and improves control of the overall weed spectrum.

University researchers have found soybean yields are highest when a sequential application of residual herbicides with multiple sites of action is used. A 3-year weed seedbank study conducted by Purdue University showed the overlapping residual program of Authority^® brand herbicides followed by Anthem^® MAXX herbicide out-yielded the non-FMC programs by 4-5 bushels per acre of soybeans.

In the same study, researchers found the overlapping residual herbicide program reduced the soil seedbank. This program reduced waterhemp seed in the seedbank by nearly 50%. Weed control dropped off dramatically when treatments did not include layered residual herbicides, producing more weed escapes and weed seed to return to the soil seedbank.

The building blocks of a herbicide program

When it comes to weighing herbicide options for an overlapping strategy, longevity is one of the most important features. Building a program based on the most effective and longest residual herbicides with multiple modes of action allows growers to start and stay clean of weeds throughout the entire season.

FMC offers a herbicide portfolio that includes solutions like Authority^® Supreme herbicide, Authority^® Edge herbicide and Anthem® MAXX herbicide, which are built on the industry’s most effective Group 14 and 15 herbicide active ingredients: sulfentrazone and pyroxasulfone. Both active ingredients have the longest residual, providing better weed control over an extended period.

Effective active ingredients result in impactful solutions. This portfolio is designed to ensure growers can build and execute an overlapping residual herbicide program that helps get them to the goal of weed-free canopy closure and help maximize yield potential.

Without the use of an overlapping residual herbicide program, soybean growers risk yield loss and a growing weed seedbank. With an overlapping weed control program based on residuals, growers can be more effective in optimizing results and helping prevent weed escapes today that will set the stage for more successful seasons down the road. 

For more information on overlapping residual herbicides and FMC solutions, visit lockin.ag.fmc.com.

 A Southern Illinois University study in 2022 looked at the influence of herbicide programs on the soil seedbank for waterhemp. Researchers found the overlapping residual program of Authority® Edge herbicide followed by Anthem® MAXX herbicide provided 99% control of waterhemp in this trial 116 days after it was applied. In the same study, researchers looked at the surviving biomass of waterhemp prior to harvest. The treatment consisting of Authority Edge herbicide followed by Anthem MAXX herbicide had less than a quarter pound of waterhemp biomass, while the other two programs that had postemergent herbicides with no residual yielded 8-10 pounds of waterhemp. This demonstrates the impact of FMC’s overlapping residual herbicide program to reduce the weed seedbank and limit seed-producing biomass.

Always read and follow all label directions, precautions and restrictions for use. Some products may not be registered for sale or use in all states. FMC, the FMC logo, Anthem and Authority are trademarks of FMC Corporation. ©2023 FMC Corporation. All rights reserved. 23-FMC-0995 03/23