39 U.S. Code § 3014 - Nonmailable plants
(1) Whenever the Secretary of Agriculture establishes a quarantine under section 8 of the Plant Quarantine Act, prohibiting the transportation by common carrier of any plant from any State or other geographic area, the Secretary shall give notice of the establishment of such quarantine to the Postal Service in writing.
(2) Upon receiving any such notice under paragraph (1), the Postal Service shall ensure that copies of such notice are prominently displayed at post offices located within each State or area covered by the quarantine, and shall take any other measures which the Postal Service considers necessary in order to inform the public both of the establishment of such quarantine and of relevant provisions of this section and sections 1716B and 1716C of title 18 in connection therewith.
(b) Any plant, the transportation of which by common carrier from any State or other area is prohibited or restricted under any quarantine referred to in subsection (a), is nonmailable matter, and may not be accepted by the Postal Service or conveyed in the mails, if the matter involved is tendered for transmission through the mails from such State or area or if such matter first enters the mails within such State or area.
(c) The Postal Service shall, after consultation with the Secretary of Agriculture, prescribe rules and regulations permitting the mailing of a plant, and otherwise making subsection (b) of this section inapplicable with respect to such plant, if the method or manner of mailing such plant would be consistent with the procedures set forth in the rules and regulations prescribed under the fourth sentence of section 8 of the Plant Quarantine Act (relating to the inspection, disinfection, and certification of, and other conditions for, the delivery and shipment of plants otherwise subject to quarantine).
(d) For the purposes of this section—
(1) “Plant Quarantine Act” means the Act entitled “An Act to regulate the importation of nursery stock and other plants and plant products; to enable the Secretary of Agriculture to establish and maintain quarantine districts for plant diseases and insect pests; to permit and regulate the movement of fruits, plants, and vegetables therefrom, and for other purposes”, enacted August 20, 1912  (37 Stat. 315 et seq.); and
(2) “plant” means any class of plants, fruits, vegetables, roots, bulbs, seeds, or other plant products, any class of nursery stock (as defined by section 6 of the Plant Quarantine Act),  and any other article or matter which is capable of carrying any dangerous plant disease or pest.
 See References in Text note below.
Source(Added Pub. L. 100–574, § 1(a)(1),Oct. 31, 1988, 102 Stat. 2892.)
References in Text
The Act of Aug. 20, 1912, referred to in subsec. (d), is act Aug. 20, 1912, ch. 308, 37 Stat. 315, as amended, which was classified generally to chapter 8 (§ 151 et seq.) of Title 7, Agriculture, prior to repeal by Pub. L. 106–224, title IV, § 438(a)(1),June 20, 2000, 114 Stat. 454. Sections 6 and 8 of the Act were classified to sections 152 and 161, respectively, of Title 7. For complete classification of this Act to the Code, see Tables.
“(a) In General.—This Act and the amendments made by this Act [enacting this section and sections 1716B and 1716C of Title 18, Crimes and Criminal Procedure] shall become effective on the earlier of—
“(1) the 366th day after the date of the enactment of this Act [Oct. 31, 1988]; or
“(2) the first date as of which all rules and regulations required to be prescribed under the amendments made by this Act have first been published in the Federal Register. [For publication of regulations, see 54 F.R. 49978, Dec. 4, 1989.]
“(b) Regulations.—Nothing in this section shall prevent the United States Postal Service from taking any action which may be necessary to prepare and issue, as soon as possible after the date of the enactment of this Act, any rules and regulations which the Postal Service is required to prescribe under any of the amendments made by this Act.”