Applicants for licensing shall elect to be examined for certification in one or more of the following categories:

1. (a) Control of insects, mites, and other invertebrates.
2. (b) Control of plant pathogens.
3. (c) Control of nematodes.
4. (d) Control of vertebrate pests.
5. (e) Control of weeds.
6. (f) Defoliation.

7. (g) Plant growth regulation.

   The examination shall be prepared and administered by the director.