The director may classify licenses to be issued under the provisions of this chapter. These classifications may include but are not limited to pest control operators, ornamental sprayers, agricultural crop sprayers or right-of-way sprayers; separate classifications may be specified as to ground, aerial, or manual methods used by any licensee to apply pesticides.

Each such classification shall be subject to separate testing procedures and requirements. No person shall be required to pay an additional license fee if such person desires to be licensed in one or all of the license classifications provided for by the director under the authority of this section, except as provided for in RCW 17.21.110.