Dormant Spray Water Quality Initiative

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.