California Code, Government Code - GOV § 25842.5

(a) The board of supervisors may provide the same services and exercise the powers of mosquito abatement districts or vector control districts formed pursuant to the Mosquito Abatement and Vector Control District Law, Chapter 1 (commencing with Section 2000) of Division 3 of the Health and Safety Code within both the unincorporated and incorporated territory of the county.

(b) Before exercising that authority within incorporated territory, the consent of the city council shall first be obtained.Before exercising the authority granted pursuant to this section, the board of supervisors shall hold a public hearing on the proposal. Notice of the hearing shall be given pursuant to Section 6061 in a newspaper of general circulation in the county.