Cal. Food and Agricultural Code § 77121

(a) The secretary shall establish a list of producers eligible to vote on implementation of this chapter. In establishing the list, the secretary shall require that handlers, producers, and others submit the names and mailing addresses of all producers. The secretary also may require that the information provided include the quantity of walnuts produced by each producer or, in the alternative, may establish procedures for receiving the information at the time of the referendum vote specified in Section 77123. The request for the information shall be in writing. The information shall be filed within 30 days following receipt of the written request. (b) Any producer whose name does not appear on the secretary’s list may have his or her name placed on the list by filing with the secretary a signed statement identifying himself or herself as a producer. Failure to be on the list does not exempt the producer from paying assessments. (c) Proponents and opponents of the commission may contact producers on the list in a form and manner prescribed by the secretary so long as all expenses associated with the contacts are paid in advance.