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Pesticide Seed Coatings are Widespread but Underreported

Lack of data may complicate efforts to evaluate the value of different pest management strategies, while also protecting human health and the environment.


Expert Contacts

Aimee Code, Pesticide Program Director, Xerces Society for Invertebrate Conservation

541-232-9767  |  [email protected]

Paul Esker, Assistant Professor of Epidemiology and Crop Pathology, Penn State

814-865-0680  |  [email protected]

Margaret Douglas, Assistant Professor of Environmental Studies, Dickinson College

717-254-8393  |  [email protected]

Claudia Hitaj, Research and Technology Associate, Luxembourg Institute of Science and Technology

[email protected]

UNIVERSITY PARK, Pa.; March 18, 2020—Seed coatings incorporating pesticides such as neonicotinoids, many of which are highly toxic to both pest and beneficial insects, are increasingly used in the major field crops. This pesticide use is going underreported, in part, because farmers often do not know what pesticides are on their seeds, according to an international team of researchers. The lack of data may complicate efforts to evaluate the value of different pest management strategies, while also protecting human health and the environment.

“We reviewed existing evidence, as well as proprietary and novel government data, on seed treatment usage and found that many farmers either did not know what pesticides were on their seeds or falsely assumed that seed treatments did not include certain pesticides,” said Paul Esker, assistant professor of epidemiology and crop pathology, Penn State. “This lack of knowledge could lead to overuse of pesticides, which could harm the environment and farmers’ health.”

The team analyzed proprietary data from Kynetec, a third-party global marketing and research firm that maintains one of the most comprehensive datasets on pesticide use in the United States, collected from 2004–2014. They found that the use of seed treatments in the US grew over the past decade, particularly in corn and soybean production. In the 2012 to 2014 period, 90 percent of corn acres and 76 percent of soybean acres were grown with treated seeds. Of the insecticides applied to seeds, neonicotinoids accounted for roughly 80 percent.

Next, the researchers analyzed farmers’ responses to questions about pesticide-coated seeds documented in the Agricultural Resource Management Survey (ARMS)—the U.S. Department of Agriculture’s primary source of information on the production practices, resource use and economic well-being of America’s farms and ranches. Specifically, they examined farmer responses to the ARMS for cotton in 2015, corn in 2016, wheat in 2017 and soybean in 2018.

They found that around 98 percent of farmers were able to provide the names of the field-applied pesticides used on their cotton, corn, wheat or soybean crops. By contrast, only 84 percent of cotton growers, 65 percent of corn growers, 62 percent of soybean growers, 57 percent of winter wheat growers and 43 percent of spring wheat growers could provide the name of the seed-treatment product on their crops. The rest either did not answer the survey question or specified that they did not know.

The researchers also found that, in 2015, cotton growers reported that 13 percent of total acreage was not treated with an insecticide and 19 percent was not treated with a fungicide, while simultaneously reporting the use of products containing those types of pesticides on that acreage.

The study is published today (February 18, 2020) in the journal BioScience.

“One of the most important findings of this study is that farmers know less about pesticides applied to their seeds than pesticides applied in other ways,” said Margaret Douglas, assistant professor of environmental studies, Dickinson College. “This is likely because seed is often sold with a ‘default’ treatment that contains a mix of different pesticide active ingredients, and the treated seed is exempt from some labeling requirements. Without knowing what is on their seeds, it is nearly impossible for farmers to tailor pesticide use to production and environmental goals.”

According to the study’s lead author Claudia Hitaj, research and technology associate, Luxembourg Institute of Science and Technology, the lack of information on the use of pesticidal seed treatments means that a significant portion of pesticide use, particularly for active ingredients that are applied almost exclusively as seed treatments, is not captured in existing pesticide-use datasets.

“Reliable data on pesticide use is needed by regulators, farmers and researchers to increase agricultural production and profitability and to protect human health and the environment from the adverse effects of pesticides,” she said.

By comparing the data Kynetec collected during the 2004–2014 window to that collected in 2015, when Kynetec stopped offering information on seed treatments, the team found a significant drop in pesticide use for a number of pesticides known to be used as seed treatments. The researchers used clothianidin as an example of what can happen as a result of poor tracking of pesticide-treated seed use.

“The removal of data on treated seed makes clothianidin use appear to drop from more than 1.5 million kg/year in 2014 to less than a tenth of a million kg/year in 2015,” said Aimee Code, pesticide program director, Xerces Society for Invertebrate Conservation. “Clothianidin is currently undergoing review by the U.S. Environmental Protection Agency, so the lost data makes it difficult to ensure accurate risk assessment.”

The team concluded that farmers, researchers and regulators could benefit from improved labelling of pesticide-treated seeds and posting of information about the active ingredients contained in treated seed products on public websites. In addition, information could be collected through sales data from seed retailers and other companies. And information about the planting location of treated seeds could help in assessing pest resistance and the local effects of pesticides on the environment.

“The lack of knowledge by farmers about the pesticides applied to seed is an example of why it is important to maintain a strong university extension system that can provide up-to-date information about different seed treatments, what these treatments do, and what the empirical data shows,” said Esker. “This is also an opportunity for further collaboration among different disciplines, like agronomy, plant pathology, entomology, economics and environmental science, to address farm issues from a whole-system perspective.”

Other authors on the paper include David Smith, former economist, Economic Research Service of the U.S. Department of Agriculture, and Seth Wechsler, agricultural economist, Animal and Plant Health Inspection Service, U.S. Department of Agriculture.

The National Science Foundation and the U.S. Department of Agriculture supported this research.




Read the BioScience article at
Sowing Uncertainty: What We Do and Don’t Know about the Planting of Pesticide-Treated Seed
Claudia Hitaj, David J Smith, Aimee Code, Seth Wechsler, Paul D Esker, Margaret R Douglas
BioScience, biaa019,

Read more about the Xerces Society’s work Reducing Pesticide Use & Impacts

Read more about Ecological Pest Management

More information about Understanding Neonicotinoids



The Xerces Society is a nonprofit organization that protects the natural world by conserving invertebrates and their habitat. Established in 1971, the Society is a trusted source for science-based information and advice and plays a leading role in promoting the conservation of pollinators and many other invertebrates. We collaborate with people and institutions at all levels and our work to protect bees, butterflies and other pollinators encompasses all landscapes. Our team draws together experts from the fields of habitat restoration, entomology, plant ecology, education, pesticides, farming and conservation biology with a single passion: Protecting the life that sustains us.

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[Note: This page was modified on 4/23/2020 to correct grammatical errors in the opening sentence.]