NDSU Finds Herbicide-Resistant Kochia in North Dakota
Researchers report kochia populations that survive Aim and Sharpen treatments, prompting farmers to revise soybean herbicide programs.
Updated on Nov. 3, 2026 in Agriculture
Live Poll
Do you think weed control on local farms is getting better or worse?
North Dakota State University researchers have found herbicide-resistant kochia populations in North Dakota, and a greenhouse study found Aim and Sharpen do not control some populations in the Minot, Berthold, Mandan, and Mott areas. Farmers are adjusting soybean herbicide programs in response to pigweed and kochia resistance.
Why it matters
Resistance to Aim, Sharpen, and glyphosate found in North Dakota and Canada is widespread, limiting the options growers have for controlling these weeds. The findings are driving changes in how farmers plan herbicide use in soybean fields.
Field results from Fargo in 2021 and 2022 showed up to 98% waterhemp control four weeks after planting with a Metribuzin mix. Control dropped off when the Metribuzin rate was reduced to half a pound or less, and the statewide extent of resistance has not been reported.
The players
North Dakota State University
A land-grant public research university whose weed science researchers conducted the kochia and pigweed studies reported in this story.
The details
NDSU researchers found the resistant populations and tested Aim and Sharpen in a greenhouse study. A multi-state trial also tested Metribuzin as a pre-application for pigweed control in Fargo, and NDSU will conduct greenhouse research on Group 14 herbicides Sulfentrazone and Flumioxazin.
Timeline
2021: Metribuzin pigweed study conducted in Fargo.
2022: Metribuzin pigweed study repeated in Fargo.
2023 growing season: Updated weed control recommendations for soybeans in the Dakotas.
Upcoming: Metribuzin-resistant soybean variety trial to be repeated this year.
Market Landscape
Resistance to Aim, Sharpen, and glyphosate has been documented across North Dakota and Canada, extending a regional pattern of herbicide-resistant weeds. The new kochia findings add to that record and push growers toward alternative chemistries and pre-emergence programs.
Soybean growers in North Dakota may need to revisit their herbicide programs, since Aim and Sharpen may not control some kochia populations. Pre-emergence options such as Metribuzin deserve review, but control can fall off at lower rates.
The takeaway
Farmers should confirm which herbicide modes of action still work on their local weed populations before finalizing soybean programs. Rotating chemistries and using pre-emergence applications can help slow the spread of resistance.
Further reading
For more on the crops and weed pressures involved, explore Agriculture coverage across the state.
More information
Find NDSU weed research information on the university's agricultural extension site.
Source note: This article includes information reported by Farm Progress.
Live Poll
Do you think weed control on local farms is getting better or worse?
