Any vegetable plant free from soil, or in soil freed from injurious insects, pests or plant diseases by methods acceptable to an authorized official may be shipped into New York State when accompanied by a certificate issued by said authorized official. Such certificate shall state that the vegetable plants are apparently free from injurious insects, pests or plant diseases and that said vegetable plants were properly treated during their growing season to prevent the establishment of injurious insects, pests or plant diseases.