If the board of supervisors finds that a mosquito control program is feasible and practical, it shall enter an order requiring all persons, firms, associations and corporations who are to engage in planting or producing rice for the following crop year to obtain permits for such rice production. The fee for such permits shall be based on the total acreage of the applicant which is to be devoted to rice production. The board of supervisors may fix the cost per acre of such permit so that each of the estimated acres of rice to be planted during the following crop year shall bear its pro rata part of the total cost of the program.