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Residual Powerhouses - The Driving Force Behind Effective Weed Control

March 10, 2022 10:00 a.m.


When deciphering all the herbicide options, there’s one characteristic a weed control program should be built on: residual.

Growers fight with germinating weeds from April to October. Having a residual herbicide in the sprayer at the pre-emergent and post-emergent stages can help address this wide germination window. They give growers a constant control force in the field to target weeds before or while they germinate.

Key broadleaf weeds, like Palmer amaranth and waterhemp, require growers to adopt a systematic approach to manage them. This entails starting clean with a burndown that leverages a long residual followed by a post-emergent application that overlays another residual to stop weeds from emerging. This system is contingent on keeping herbicide active ingredients available and activated earlier and later in the season.

Making the Residual Herbicide Life Last Its Longest

Utilizing herbicides with a long-lasting residual is a best practice. However, it’s important to ensure the herbicides deliver the maximum residual life and provide coverage through to canopy closure.

For a grower to maximize their herbicides’ effective residual life, several factors with significant influence on residual must be accounted for. These are dependent on the growing environment or the applicator and can make or break if a grower makes the most of their herbicides’ effective residual life.

Soil Degradation

Herbicides naturally degrade in the soil but that pace varies. Soil type plays a big role in how long a herbicide persists effectively in the soil. For example, soil that is porous and prone to leaching following a rain event lessens an herbicide’s staying power. Examining and knowing each field’s type allows a grower to pinpoint herbicide options tailored for their different soil types.

Adequate Rates

Use rate has a significant effect on whether or not an herbicide’s residual is maximized. Combining different herbicides or spiking the sprayer tank with other products are easy ways operators can alter an herbicide’s use rate in the tank.

Weighing Powerhouse Options

When building out an herbicide program, FMC’s solutions deliver the residual and diverse options growers need. Through the FMC portfolio, growers are offered choice and the opportunity to incorporate, from a preemergent standpoint, multiple modes of action through the Authority® brand herbicides lineup to tackle specific needs a grower might have. In the post-emergent stage, an option like Anthem® MAXX herbicide allows a grower to add another mode of action to the tank to help control or stop weeds like Palmer amaranth or waterhemp.

Tools like Authority Supreme and Edge herbicides offer growers an optimized ratio of the industry’s best Group 14 and Group 15 herbicides, sulfentrazone, and pyroxasulfone. These solutions are built for growers with wide-ranging soil and field conditions from light soils to heavy, high organic matter soils. Additionally, delivering long-lasting residual weed control against weed species like waterhemp and Palmer amaranth other chemistries struggle to manage.

Ultimately, a successful weed management program is built on a backbone of multiple different, effective chemistries and putting them out together. Through this strategy, growers end up delivering a multifaceted approach that drives residual activity in the pre-emergent and post-emergent stages that eliminate the chances for weeds to germinate.

To learn more about residual herbicides and solutions to incorporate into your weed management plans, talk to your FMC representative or visit

LEGAL: 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 or an affiliate. ©2022 FMC Corporation. All rights reserved. 22-FMC-0164 2/22