Nine out of 10 farmers with resistant weeds reported using hand hoeing as a management practice. Other tools for managing resistance were cultural practices, such as crop rotation and cover crops, and to a lesser extent chemical or mechanical tillage.

“One of the biggest concerns of this workgroup is the potential impact that weed resistance might have on use of no-till and conservation-tillage practices,” Larson said. “There is a need to document the extent of the problem, the potential economic impacts and what farmers are doing to combat it.”

Farmers in the survey say the biggest change in tillage practices before and after weed resistance was a reduction in the use of no till practices. The survey also indicated that after the onset of weed resistance, they tended to reduce their use of Roundup Ready cotton, while increasing use of WideStrike and LibertyLink cotton.

About 63 percent of farmers surveyed rated their resistant weed management practices as being effective to very effective. “On average, all farmers thought that they were being very successful on average with their practices,” Larson said.

Forty-eight percent of farmers reported that prior to weed resistance, they had weed control costs of $50 or more per acre. After weed resistance on their farm, 92 percent of farmers reported weed control cost had exceeded $50 per acre.

erobinson@farmpress.com