Neonicotinoid Seed Treatment Study

Science Center Objects

Neonicotinoids are a new class of insecticides chemically related to nicotine. Like nicotine, they act on receptors in the nerves and are generally much more toxic to insects, than they are to mammals and other higher organisms. Their use has increased rapidly over the last decade, driven in large part by their use for seed coating. Seed coating is when a seed is treated with an insecticide prior to planting. Previous research has focused on the effect of neonicotinoid insecticides applied to corn and soybeans. However, many other crops also use neonicotinoid seed coatings. For example, in California, lettuce is grown from neonicotinoid treated seeds. Because of the different climate, irrigation patterns, and growing seasons in California, research is needed to determine the environmental transport of neonicotinoids to the state's aquatic systems.

Lettuce Field in Salinas Valley, California

Lettuce Field in Salinas Valley, California


This study will provide data on the transport of neonicotinoid insecticides used as seed coatings to surface waters via irrigation runoff. The study will also examine and quanify the presence of neonicotinoids in field soils.

Science Plan

In the Spring of 2019 and 2020, three trial plots and one control plot will be established at a University of California research farm in the Salinas Valley. These separate plots will be planted with lettuce seeds treated with 1) the neonicotinoids clothianidin and imidacloprid, 2) untreated seeds that receive a neonicotinoid drenching treatment after planting, and 3) seeds with no neonicotinoid applications (control plot).

Irrigation runoff water will be collected from each plot following 5 irrigation events and analyzed by the USGS Organic Chemistry Research Laboratory for neonicotinoids. Additionally, at the beginning and end of the growing season, surface soil samples will be collected from each plot and analyzed for neonicotinoids. Finally, once during the first year of the study, shallow (0-1 meter) soil cores will be collected from the neonicotinoid drenched plot and the control plot. The cores will also be analyzed for neonicotinoids. In addition to the environmental samples analyzed, a number of quality control samples and methodologies will be used to validate the sampling and laboratory procedures. The project and results will be described in a peer-reviewed journal article and the results of all environmental samples will be stored in the USGS National Water Information System database.

Relevance and Benefits

This project addresses the following water science aims:

  • Understand ecosystems and predict ecosystem change
  • Provide society with information regarding the quality of water
  • Assess water resources and their suitability to meet human and ecosystem needs

The project also addresses USGS environmental health science goals, such as to:

  • Identify, prioritize, and detect contaminants and pathogens of emerging environmental concern
  • Reduce the impact of contaminants on the environment, fish and wildlife, domestic animals, and people
  • Discover the complex interactions between and combined effects of exposure to contaminants and pathogens