Section 27. The director, with the approval of the commissioner, after a duly advertised public hearing with notice to interested parties, may prohibit, for such periods and under such conditions as he may impose, the delivery within the commonwealth of nursery stock, fruits, plants and parts thereof from outside the commonwealth when in his opinion they are likely to be infested with insect pests or disease or are likely to act as a carrier thereof. With the approval of the commissioner, he may make and issue such rules and regulations as may be needed to carry out sections sixteen to thirty-one, inclusive, and may in such rules and regulations establish fees for registration or inspection. He may also enter into reciprocal agreements with other states under which nursery stock owned by nurserymen and dealers of such states may be sold or delivered in this commonwealth without the payment of a registration or inspection fee; provided, that like privileges are accorded in such other states to nurserymen and dealers of this commonwealth. He may publish information about such insects and disease as come within his observation.