Section 156, acts Aug. 20, 1912, ch. 308, § 2, 37 Stat. 316; Pub. L. 100–449, title III, § 301(f)(3)(B), Sept. 28, 1988, 102 Stat. 1869; Pub. L. 103–465, title IV, § 431(d)(2), Dec. 8, 1994, 108 Stat. 4968, required that Secretary of Agriculture be notified of arrival of nursery stock at port of entry, prohibited forwarding without notification, and provided for inspection before shipment.

Section 157, act Aug. 20, 1912, ch. 308, § 3, 37 Stat. 316, set forth marking requirements for entry of nursery stock into United States.

Section 158, act Aug. 20, 1912, ch. 308, § 4, 37 Stat. 316, related to marking and inspection of imported nursery stock for interstate shipment.

Section 159, acts Aug. 20, 1912, ch. 308, § 5, 37 Stat. 316; Pub. L. 97–432, § 1(1), Jan. 8, 1983, 96 Stat. 2276, related to regulation of importation of plant products other than nursery stock.

Section 160, acts Aug. 20, 1912, ch. 308, § 7, 37 Stat. 317; Pub. L. 97–432, § 1(2), Jan. 8, 1983, 96 Stat. 2276, authorized regulations prohibiting importation of nursery stock or other plant products to prevent introduction into United States of any tree, plant or fruit disease or any injurious insect.

Section 161, acts Aug. 20, 1912, ch. 308, § 8, 37 Stat. 318; Mar. 4, 1917, ch. 179, 39 Stat. 1165; Apr. 13, 1926, ch. 135, 44 Stat. 250; Pub. L. 95–439, § 4, Oct. 10, 1978, 92 Stat. 1062; Pub. L. 97–432, § 1(3), Jan. 8, 1983, 96 Stat. 2276; Pub. L. 104–127, title IX, § 911, Apr. 4, 1996, 110 Stat. 1185, authorized quarantine of any State, territory, or district of the United States in order to prevent the spread of a dangerous plant disease or insect infestation.