Dormant Spray Water Quality InitiativeBack to Environmental Monitoring Branch
Spraying of Central Valley orchard crops during cold weather, when the trees are dormant, kills overwintering arthropod pests (such as scales and mites) and diseases. It helps to keep these destructive pests under control through the growing season. However, the organophosphate insecticides used as dormant sprays cause problems when drift occurs or when rainfall washes residues into rivers and streams. Through its Dormant Spray Water Quality Initiative, DPR works to prevent aquatic toxicity from residues of diazinon and chlorpyrifos in the Sacramento and San Joaquin Rivers.
- Fact sheet, PDF (79 kb) Rules for dormant season insecticides (Español, PDF) (138 kb)
- Regulations, PDF (23 kb) pertaining to the use of dormant spray insecticides and mitigation of surface water contamination
- Memos, reports, protocols and other publications from the Surface Water Protection Program
- Archived documents including preliminary and draft regulation documents.
For content questions contact:
Phone: (916) 324-4072