Although the year on the calendar may be changing, the weeds lurking across Dakota fields remain the same for many across the region this growing season.

Foxtail, kochia, waterhemp and wild oats are the four main weeds that farmers need to watch out for in 2025, says Joe Ikley, North Dakota State University Extension assistant professor and weed specialist.

“The grass weeds are becoming more problematic,” he explains. “We continue to find more resistant populations to group one and group two herbicides, which are what drives our grass control in small grains and specialty crops.”

Although broadleaf weeds kochia and waterhemp still were prevalent in 2024, Ikley says kochia populations were better kept in check this past year than they were in 2023. “Kochia does better in drier conditions, and with the amount of moisture we had this year, it wasn’t as rampant," he says.

Resistant weeds lurking

Herbicide resistance in these weed species is still being studied by NDSU, and Ikley says to reach out to NDSU if resistant populations are suspected to be present. “Annually, NDSU will test populations of wild oat and green foxtail resistance,” he says. “If farmers can get those weeds to us at NDSU, we can test them to get those farmers an answer on what chemistries may or may not work.”

Related:Fight weeds on multiple fronts with integrated approach

If weeds do show herbicide resistance, Ikley says there are a few options for producers to manage those populations. “Ideally, we rotate to a crop that gives you a different option, so any crop that is Roundup Ready is going to be one of the best ways to handle green foxtail or wild oat populations,” he says.

Ikley explains that he always recommends some type of crop rotation incorporated into management plans to diversify herbicide programs from year to year. Aside from crop rotation, he says that relying on older chemistries can help control these resistant weeds.

Best management practices

“Keep a good field history,” Ikley says. “Knowing what weeds were present at harvest, you can probably bank that they will be there again the next year.” Knowledge is power for weed control by knowing what weeds you’re going after each year in each field.

“Make sure you’re rotating chemistries across seasons, but also within an application, to help delay the onset of resistance,” he says. “Utilize the time you have this winter to get an herbicide program lined up.”

No matter the weed or herbicide, Ikley says that getting the application timing correct is a must for best control. “We want to get those weeds when they’re small with our postemergence applications. Take this time to do a lot of planning, but be timely once we get into the season.”

Related:What’s new with herbicides in 2025?

For more insight into weed control and management, contact your local extension office.