(a) As a minimum requirement for certification, a private applicator must demonstrate a practical knowledge of pest problems and integrated pest management practices associated with agricultural operations according to standards prescribed by the department. Competence in the use and handling of pesticides shall be determined on the basis of written examinations prepared by the department and as appropriate, performance testing, based upon standards set by the department. Such examinations and testing shall include general standards applicable to all categories and additional standards specifically identified for each category or subcategory in which the applicator is to be classified.