Iowa State leads project to combat weeds resistant to herbicides

Harrison County is home to a new project focused on combating weed resistance as part of a statewide pest resistance management program led by Iowa State University.

A team of local farmers, landowners, agronomists, crop advisers, bankers, seed and chemical company representatives, and Iowa State University Extension and Outreach specialists are addressing the increasing threat of herbicide resistant weeds, including Palmer amaranth.

Launched in 2017, the Iowa Pest Resistance Management Program is a statewide effort to slow the development of pest resistance using a collaborative approach to promote pest resistance management practices.

The Harrison County team includes farmer cooperators who will help evaluate and demonstrate the cost-effectiveness of weed resistance management for 2018 and beyond.

“I am extremely pleased in how this project is evolving, the interest that it is receiving, and especially our team,” said Larry Buss, a Harrison County farmer and leader of the project. “This team is devoting time and energy to this project because they all feel, as I do, that we have got to get on top of this resistance issue. If we do not, the results will be reduced crop yields and increased production costs, both which will decrease Iowa farmer profitability.”

Palmer amaranth was first discovered in Iowa in 2013 in Harrison County. It is of great concern to farmers due to its competitiveness, high growth rate, prolific seed production and demonstrated ability to evolve resistance to herbicides. Once established in a field, weed management costs may rise significantly.

“Combating weed resistance requires both a short-term and a long-term focus and adaptive management as we learn what works and what does not work,” Buss said.

In addition to combating Palmer amaranth, the Harrison County team will focus on improving management of widespread herbicide-resistant weeds—waterhemp, giant ragweed and marestail.

The Harrison County effort is one of several pest resistance management projects around Iowa coordinated by Iowa State, which is working with many partners to develop and implement projects across the state with farmers and their agronomic and farm advisers and agricultural professionals to devise cost-effective resistance management practices to sustain yields.

“The local teams drive these projects,” said Evan Sivesind, program manager in the Department of Entomology at Iowa State who oversees the Iowa Pest Resistance Management Program. “Farmers, crop advisers and other agriculture professionals set the direction for each project and develop strategies that address the issues facing farmers in their area. The Harrison County project has a great team in place that really understands the local landscape and the specific challenges farmers are facing in the area.”

In Harrison County, growing conditions and management practices vary widely. Field demonstrations will take place in both the Loess Hills and the Missouri River Valley. The viability of recommended resistance management practices will be tested and demonstrated in the context of local cropping systems.

Results will be shared through local field days, newspaper articles, handouts, social media and on protectiowacrops.org, which is part of Iowa State’s Integrated Pest Management website.

The Iowa Pest Resistance Management Program is a collaboration of a broad cross-section of the Iowa agriculture industry, including the Iowa Corn Growers Association, Iowa Farm Bureau Federation, Iowa Soybean Association, Iowa Soybean Research Center, Agricultural Biotechnology Stewardship Technical Committee, United States Herbicide Resistance Action Committee, United States Insecticide Resistance Action Committee, Agribusiness Association of Iowa, the Iowa Chapter of the American Society of Farm Managers and Rural Appraisers, Iowa Independent Crop Consultants Association, Iowa Institute for Cooperatives, Practical Farmers of Iowa, the Soil and Water Conservation Society, Iowa Department of Agriculture and Land Stewardship and Iowa State’s College of Agriculture and Life Sciences.