Section 31. Whenever the director finds that any town or part thereof is infested with the European corn borer or other insect pest, except the gypsy and brown tail moth, or with a plant disease which in his opinion is likely to spread to other parts of the commonwealth or to other states, he may, after a duly advertised public hearing, and with the approval of the commissioner, issue an order stating the insect pest or plant disease to be guarded against, and prohibiting, for such periods and under such conditions as he deems necessary, the transportation to or from such town or part thereof, of any specified trees, plants, shrubs or other vegetable growths or products, and any specified containers or other articles by means of which such an insect pest or plant disease is or is likely to be carried. The order aforesaid shall be advertised in a newspaper published in each town where it is to be effective or in a newspaper of general circulation in the county where the town is situated. Whoever violates any order issued under this section or whoever offers any hindrance to the carrying out of such order shall be punished by a fine of not less than twenty-five nor more than three hundred dollars.