Mich. Comp. Laws § 290.564

Sec. 14. (1) Whenever 800 of the growers, of which not more than 200 are in the same district, petition the commission, the commission shall conduct a referendum among the growers of the state to determine the rate of supplemental assessment for special projects. (2) The supplemental assessment provided for in subsection (1) shall be collected and remitted to the commission in the same manner as provided in section 12. The referendum shall be conducted in a manner to protect the purity of the ballot. (3) If a majority of the growers voting upon the question vote in favor of the proposed change, the assessment shall be ineffective in the year in which it is voted unless the change is published before June 1 of that year. (4) The total rate of supplemental assessment shall not exceed 25 cents per hundredweight.