The EPA must do more to combat weed resistance to common herbicides, the agency’s inspetor general said in a new report.
The Environmental Protection Agency Office of Inspector General released the June 21 to review the agency’s handling of a growing problem among U.S. farmers.
Many crop growers in the Midwest and the South are struggling with weeds like palmer amaranth and pigweed that don’t die when sprayed with Monsanto’s glyphosate, the most commonly used herbicide in the world. Decades of spraying the popular weedkiller alongside corn, soybeans, cotton, and other crops genetically engineered to withstand glyphosate has facilitated the evolution of invasive weeds.
Although the EPA uses the pesticide registration process to collect information on health and environmental risks from pesticides used on herbicide-resistant weeds, the agency collects little to no information on the synergy—the increased potency of chemicals that are mixed—of pesticides, the report said.
The Inspector General also found that herbicide labels don’t always include information on the chemical mechanism that explains how the herbicide kills the plant, which can result in improper spraying of weedkillers.
The EPA also has failed to provide adequate information on tracking resistance, the report said.
“There is a lack of communication and collaboration between the EPA and its public and private stakeholders regarding herbicide resistance management,” according to the report’s summary. “This limits the reach of actions proposed and taken by the EPA, the development of meaningful alternatives, and the agency’s ability to proactively respond to herbicide resistance in the field.”
In a March 23 response to the report, Wendy Cleland-Hamnett, acting assistant administrator of the EPA’s Office of Chemical Safety and Pollution Prevention, said the agency would complete draft plans to improve data collection and communication with scientists, government agencies, and industry by March 2018.
However, Cleland-Hamnett said the EPA would not develop performance measures to assess the agency’s success in slowing the spread of herbicide resistance because it would be “beyond the scope” of the agency’s regulatory authority.