The state of California requires monthly reporting of agricultural pesticide use. This requirement is enforced by the California Department of Pesticide Regulation (DPR). The following explanation of this requirement is extracted from the DPR website:

The Vector-Borne Disease Section (VBDS) protects the health and well-being of Californians from diseases transmitted to people from insects and other animals.

The California Environmental Protection Agency has the primary responsibility for regulating all aspects of pesticide sales and use to protect the public health and the environment.

The California Department of Pesticide Regulation (CDPR) is one of six departments within the California Environmental Protection Agency (Cal/EPA).

The use of public health pesticides in California is a very important subject. It involves a number of programs, ranging from pesticide use reporting to the Department of Pesticide Regulation via County Agricultural Commissioners, Surveillance programs for resistance to pesticides by mosquitoes and other pests of public health importance, and training and certification of applicators of public health pesticides. Information on these subjects can be found under this general category. Also included are links to other resources on use and safety of public health pesticides.