DPR Proposes Regulations for Tree-Hole Fumigation
The California Department of Pesticide Regulation (DPR) is proposing new regulations to permanently allow the use of 1,3-dichloropropene (1,3-D) to fumigate individual tree-holes, also known as tree planting sites, with additional use restrictions. The proposed action updates existing 1,3-D application requirements to create a specific field fumigation code for reporting the use of tree-hole method applications. DPR previously granted a three-year interim approval for this method in September 2024, following a request from the Tehama County Agricultural Commissioner. The department is proposing to make permanent most of the provisions described in the interim approval for the individual tree-hole method, including timing and setback requirements, to allow continued use beyond its expiration in September 2027. The proposal adds more stringent limits on the number of tree holes per acre that can be treated with 1,3-D.
Submit a Public Comment
The department has opened a 45-day public comment period to collect feedback on the proposed changes, through December 14, 2026. Comments can be submitted online through DPR’s SmartComment public comment portal, by email to dpr26006@cdpr.ca.gov, or by U.S. mail. Mailed comments must be sent to:
Ashley Anderson, Regulations Coordinator
Department of Pesticide Regulation
1001 I Street, P.O. Box 4015
Sacramento, California 95812-4015