The director may do any of the following:

1. (a) Certify as to the pest freedom of plants which may have been inspected or registered or may certify as to the true pest condition of the plants.
2. (b) Issue tags, labels, or certificates in evidence of inspection or registry.
3. (c) Supervise or conduct any special treatments which may be necessary to insure the pest freedom of plants for propagation or planting purposes.
4. (d) Fix uniform fees to be charged for inspections, registrations, certifications, and special treatments. The fees shall be based upon the approximate cost of the service which is rendered.