By Scout Nelson
Kochia is a common weed found in many fields across South Dakota and nearby Great Plains states. It starts growing early in the season and must be managed before planting crops. In no-till farming systems, herbicides are a key tool to control kochia.
One such herbicide, saflufenacil (known by the brand name Sharpen), is often used before planting and has been very effective in the past. However, too much use of saflufenacil over time has caused some kochia plants to become resistant.
This problem has already been seen in North Dakota and parts of Canada. To investigate the issue locally, South Dakota State University tested weed samples to see if the same resistance is happening in South Dakota.
A population of kochia from Northeast South Dakota showed strong resistance. When treated in a greenhouse with the normal rate of saflufenacil (1 fluid ounce per acre), none of the treated plants from that region died.
In contrast, most plants from a Southeast South Dakota population died under the same treatment. These findings confirm that saflufenacil-resistant kochia now exists in Northeast South Dakota.
Researchers are now testing kochia from other parts of the state to find out how widespread the resistance is. In the meantime, experts suggest farmers reduce their reliance on just one herbicide.
Mixing herbicides like saflufenacil with others such as paraquat or dicamba can improve weed control and reduce the risk of more resistance developing.
Options include using a different herbicide, mowing, tillage, or even hand-pulling the weeds. These steps help stop the weeds from making seeds and spreading further.
Photo Crdit: south-dakota-state-university
Categories: South Dakota, Education