By Scout Nelson
Researchers including Debalin Sarangi, Navjot Singh, Lisa Behnken, Ryan Miller, and Tom Peters report on the first confirmed case of glufosinate-resistant waterhemp in Minnesota. This is likely the second such case in the United States, following a report from Illinois in 2026. The discovery raises concerns about increasing herbicide resistance in farming systems.
Glufosinate is a commonly used herbicide that controls weed by stopping an important plant process called nitrogen metabolism. It works by blocking an enzyme that helps plants grow. When applied, it causes damage to plant leaves within hours. However, its effectiveness is now being challenged due to resistance in certain weed populations.
Earlier studies in Minnesota show that waterhemp has already developed resistance to multiple herbicide groups. At some locations, researchers confirm resistance to six different herbicide types, leaving glufosinate as the main post-emergence option. With the discovery of resistance to glufosinate, farmers may soon face situations where no effective chemical options remain.
The resistant population is identified after a farmer reports control failure in 2023. Researchers collect seeds and conduct greenhouse and field trials. Results show that treated plants are damaged but survive by growing again from new points. Studies reveal that this waterhemp population is about three times more resistant than normal plants. Field results show only about 60 percent control with standard herbicide use.
Further research suggests that the resistance is not caused by a direct change in the plant target but by other biological mechanisms. Scientists continue to study this process for better understanding.
Experts warn that resistance may spread further across the Midwest. They advise farmers to use strong pre-emergence herbicides, rotate different herbicide groups, and include non-chemical methods such as crop rotation and field management practices.
This discovery highlights the need for careful use of herbicides and better planning to protect crop production and reduce the risk of resistance in the future.
Photo Credit: gettyimages-fotokostic
Categories: Minnesota, General, Sustainable Agriculture