Cal. Food & Agric. Code § 13166

The director shall limit the use of any pesticide granted a certificate of interim registration to specific uses within a pest management system meeting the requirements of subdivision (a) of Section 13164. The director may place additional restrictions on the use of any pesticide granted a certificate of interim registration, including, but not limited to, requiring a restricted material permit or the written recommendation of a specially trained pest control advisor or specially trained certified private applicator, or limiting the quantity, area, and manner of application.