California Code, Business and Professions Code - BPC § 8556

(a) Licensed contractors acting in their capacity as such, may remove and replace any structure or portions of a structure damaged by wood destroying pests or organisms if that work is incidental to other work being performed on the structure involved or if that work has been identified by a structural pest control inspection report. Licensed contractors acting in their capacity as such may apply wood preservatives directly to end cuts and drill holes of pressure treated wood, and to foundation wood as required by building codes, as well as to fencing and decking, by brush, dip, or spray method and need not obtain a license under this chapter for performance of that work, provided a disclosure in the following form is submitted to the customer in writing: “The application of a wood preservative is intended to prevent the establishment and flourishing of organisms which can deteriorate wood. If you suspect pest infestation or infection, contact a registered structural pest control company prior to the application of a wood preservative.”

These exemptions do not authorize the performance of any other acts defined in Section 8505.

(b) A licensed contractor may contract for the performance of any soil treatment pest control work to eliminate, exterminate, control, or prevent infestations or infections of pests or organisms in the ground beneath or adjacent to any existing building or structure or in or upon any site upon which any building or structure is to be constructed, but the actual performance of any such work must be done by a registered structural pest control company.