RCW 15.08.260

At the time of making the regular annual tax levy the board of county commissioners of each county shall include a tax, to be known as the "horticultural tax," upon the taxable property of the county in an amount sufficient to meet the expense of inspecting and disinfecting nursery stock, fruits, vegetables, horticultural or agricultural products, and horticultural premises under the provisions of this title. Said tax shall be levied and collected in the same manner as are general taxes and when collected shall be placed in the county current expense fund.