Upon a finding by a two-thirds vote of the commission that the operation of this chapter has not tended to effectuate its declared purposes, the commission may recommend to the director that the operation of this chapter be suspended. No suspension shall become effective until the expiration of the current marketing season. The director shall, upon receipt of the recommendation, or may, after a public hearing to review a petition filed with him or her requesting the suspension, signed by 20 percent of the producers by number who produced not less than 20 percent of the volume in the immediately preceding season, cause a referendum to be conducted among the producers to determine if the operation of this chapter shall be suspended. However, the director shall not cause a referendum to be conducted as a result of the petition unless the petitioner shows by the weight of evidence that the operation of this chapter has not tended to effectuate its declared purposes. The director shall establish a referendum period, which shall not be less than 10 nor more than 60 days in duration. The director may prescribe any additional procedures that may be necessay to conduct the referendum. At the close of the established referendum period, the director shall tabluate the ballots filed during the period. If at least 40 percent of the total number of producers from the list established by the director participate in the referendum, the director shall suspend the operation of this chapter, if he or she finds either one of the following has occurred: