The reasons for controlling weeds on the farm are endless: They interfere with harvest. They rob yield. They host damaging insects. And they are plain unsightly.

Keeping weeds at bay requires various management practices. But how can farmers create the best combination of practices? The network Getting Rid of Weeds can help.

GROW is made up of agronomists, weed scientists and economists from university Extension services and USDA. They coordinate research to help farmers across the U.S. fight herbicide resistance by using a diversity of weed control strategies that complement chemical use.

“We’re a source of information that’s backed by a whole network of scientists,” says Michael Flessner, associate professor and Extension weed specialist at Virginia Tech. “We’re motivated by herbicide resistance, and that’s going to be a continued part of weed management to maximize herbicide diversity and rotation, while integrating the nonchemical side of control.”

Reliance on herbicides

Herbicide application is the main method of weed control used in the U.S. Relying on this one type of management has contributed to the development of herbicide-resistant weeds.

With GROW’s integrated weed management (IWM) approach, producers can find information about how to tackle weeds using multiple tactics. This management allows farmers the best chance to control troublesome weeds by employing a combination of mechanical, biological, cultural, chemical and prevention techniques.

ROLLER CRIMPER: This shows the thick mat of residue that a cereal rye crop can produce by planting time in some regions of the country, providing excellent weed suppression. (Claudio Rubione, GROW)

“Everybody probably has at least one glyphosate-resistant weed,” Flessner says. “Extension specialists have been saying for years that herbicide discovery and commercialization is being outpaced by the development of herbicide resistance.”

If current trends continue, Flessner cautions that farmers may run of out effective herbicides. “That’s where we’ve got to look at herbicides to continue to manage with them while using other tactics,” he says.

Weeds such as Palmer amaranth, waterhemp and kochia continue to cause problems, which is where IWM can help. Flessner says two major areas of research are in cover crops and weed seed control at harvest.

The cover crop method works by suppressing weeds from residue, while harvest weed seed control keeps them from spreading out of the combine. “We try to take that opportunity to manage weeds with an approach that will be successful in the producer’s region,” he says.

GRIND IT: A seed impact mill grinds up weed seeds and chaff residue out of the combine during harvest. This method helps prevent viable weed seeds from spreading via the combine at harvest. (Claudio Rubione, GROW)

“Cover crops won’t fit everywhere. In the mid-Atlantic and East Coast going into the South, it works really well. But some areas that are too far north, nothing is going to grow in the winter,” Flessner says. “Moving west and into the Rockies, it might not work the best there, but it is promising research, for sure.”

Categories of IWM practices

Ways to incorporate IWM can look different depending on the region and the producer, and entail these practices:

Prevention. As one of the first steps in managing weeds, prevention focuses on keeping weeds from spreading out of a field, which includes the following:

Cultural practices. These are designed to give crops a competitive advantage over weeds:

Herbicides. As an integral part of many weed management plans, herbicides can work to their potential by following these steps:

Mechanical control. These physical practices disrupt weed germination and destroy plant tissue:

Regardless of the methods preferred, farmers can find success in long-term weed management while minimizing the risk of developing herbicide-resistant weeds through an IWM approach. Farmers who are interested in incorporating IWM on their farm can find more information from GROW.