Section, act Aug. 20, 1912, ch. 308, Sec. 15, as added May 31, 1920, ch. 217, 41 Stat. 726; amended May 16, 1928, ch. 572, 45 Stat. 565; July 7, 1932, ch. 443, 47 Stat. 640; Mar. 26, 1934, ch. 89, 48 Stat. 486; Apr. 1, 1942, ch. 207, Sec. 1, 4, 56 Stat. 190, 192; Pub. L. 88-60, Sec. 1, 7, July 8, 1963, 77 Stat. 77, 78; Pub. L. 91-358, title I, Sec. 155(a), July 29, 1970, 84 Stat. 570, related to rules and regulations to prevent dissemination of dangerous plant diseases and insect infections and infestations in the District of Columbia