Section 7
SEC. 7. The Director of Agriculture is further authorized to prohibit entirely the importation of certain classes of plants or any or all parts of said plants, or other possible carriers of infestation whether visibly infested or not, when information has been received by him showing that dangerous insects or diseases exist in the countries of origin (including not only where the material was raised but also those where it has gone through), and the presence of said insects or diseases cannot be readily and economically determined on such incoming plant materials.