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Pyrethroid Control Program
Draft Pyrethroid Research Plan

During the development of the Pyrethroid Control Program (Resolution R5-2017-0057), Regional Board staff recognized that the data used to evaluate the potential for registered pyrethroid products to cause or contribute to water quality concerns contained considerable knowledge gaps. Therefore, the Pyrethroid Control Program included a provision that the Regional Board would work with stakeholders to develop a Pyrethroid Research Plan (Plan) that describes research and other special studies to inform future iterations of the control program (e.g., potential objectives, program refinement).

In 2023, Regional Board staff performed a literature review to identify any additional knowledge gaps and/or studies that may be useful to address the initial knowledge gaps identified in the Pyrethroid Control Program. In addition to the identification of scientific knowledge gaps, Regional Board staff identified research questions that will inform pyrethroid and other replacement pesticide regulations.

The Regional Board aims to use pyrethroid research to inform science-based pyrethroid management in the Sacramento and San Joaquin River Basins, thereby protecting beneficial uses. The Plan will not contain any new regulations or requirements. Rather, staff intend the Plan to serve as a basis upon which the science community may develop research proposals that will aid in addressing the Regional Board research questions.

The public comment period for the draft research plan closed on 18 September 2023.

Next Steps:

1. Revise Draft Plan
2. Develop Response to Comments
3. Release revised Plan and Response to Comments
4. Staff Workshop - 21 November 2025 at 10:30AM
• Notice of Staff Workshop and Public Hearing
• Notice of Staff Workshop and Public Hearing (Español)
5. Public Hearing - 26/27 February 2026

For project updates, please subscribe to the TMDL – Central Valley Pyrethroids email list available on the upper right corner of Pyrethroid Control Program page.