Report: Dicamba Herbicide Harming More than Just Weeds

Serious Risks of Unchecked Herbicide Impacts Highlighted on Wildlife, People

WASHINGTON, D.C. — As the Environmental Protection Agency prepares to determine whether to renew dicamba product registrations for the 2021 growing season, a new report details how the herbicides pose serious threats to wild plants and the wildlife that depend upon them. The report from the National Wildlife Federation, Prairie Rivers Network and the Xerces Society for Invertebrate Conservation Drifting Toward Disaster: How Dicamba Herbicides are Harming Cultivated and Wild Landscapes, reviews the state of the science on the potential far-reaching impacts of dicamba use.

“Dicamba herbicides pose significant threats to wild plants and the wildlife that depend upon them — even when used as prescribed on their labels,” said Lekha Knuffman, agriculture program specialist at the National Wildlife Federation. “Widespread use of dicamba throughout the growing season is harming other crops as well as wild and native plants, degrading food sources for wildlife and pollinators. This is a crossroads in being able to limit the destructive effects of dicamba. The EPA must deny permission for the continued use of this damaging herbicide across millions of acres.” 

Dicamba is a highly volatile herbicide in use across the country. Despite strong evidence of herbicide damage, the EPA’s research is wholly inadequate regarding impacts to other plants, trees, pollinators and other wildlife.

“In Illinois we’ve seen firsthand the effect that herbicide drift has on public and private lands, wildlife habitat, and farms that grow sensitive crops.” said Kim Erndt-Pitcher, habitat and agriculture programs specialist at Prairie Rivers Network. “It is the invisible threat. You can tell it’s been there, but you can’t see it happen, and in many cases, you can’t tell where it came from. Meanwhile, the EPA seems more concerned with the needs of industry and manufacturers than those of farmers and the environment."

As part of the registration determination, the EPA is likely to be considering extending in-crop dicamba use to corn.

“Opening millions of additional acres of wild, ornamental, and crop plants to off-target dicamba injury would be very alarming,” said Emily May, pollinator conservation specialist with the Pesticide Program at The Xerces Society for Invertebrate Conservation. “We need to seek long-term solutions to reduce reliance on herbicides and build more ecologically and economically resilient farm landscapes.”

The report advocates for diversifying weed management strategies to improve resilience, including choosing crop varieties that are competitive with weeds, adjusting planting dates and depths of crops to help get ahead of weed growth, and managing nutrients in ways that give crops the competitive edge.

Mounting evidence suggests that current dicamba products and uses are causing unreasonable adverse effects on the environment, even when used exactly as specified on the labels. Based on what is known of the impacts of dicamba on off target species, the report issues the following recommendations for any future decisions on reregistering dicamba for agricultural use:

  • The EPA should not renew over-the-top product registrations unless and until independent research shows with certainty that dicamba formulations will not cause off-target injury to crops and wild plants, including from vapor drift. 
  • The EPA should include a full risk assessment for animal and plant species listed under the Endangered Species Act, migratory birds, native pollinators, and aquatic life that includes direct and indirect effects from exposure to dicamba due to drift, volatilization, and runoff.
  • States should improve transparency in the injury reporting process and make data on pesticide use and distribution publicly available in a timely manner, to better ensure public health and environmental protection.
  • Greater investment is needed to support research on integrated weed management and the ecological impacts of herbicide use. Investments are also needed to develop economic and behavioral drivers that will increase adoption of these multi-tactic approaches to weed management.
  •  Increased investments are needed in technical service providers and financial and technical assistance programs that facilitate the shift to agro-ecological systems that regenerate the soil and protect air and water for people and biodiversity.

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