ABSTRACT
The discovery of 2,4-D as an herbicide during World War II was the greatest single advance in weed science and a very significant advance for agriculture (Bovey, 1980c; Burnside, 1996; Peterson, 1967; Veale, 1946). In the more than 50 years since its introduction, 2,4-D continues to be the most commonly used herbicide worldwide (Burnside, 1996). In the early 1940s, Krause at the University of Chicago and others proposed to the National Academy of Sciences that the growth-regulating properties of the phenoxys should be tested for crop destruction to limit crop production for military considerations (Bovey, 1980b ). After intensive testing by the U.S. Army and others, the phenoxy herbicides were never used in World War II. After World War II, however, the U.S. Army biologicallaboratories at Fort Detrick, Maryland, continued testing chemicals for desiccation and defoliation activity (House et al., 1967; Bovey, 1980b). In the early 1960s the South Vietnamese government requested that the U.S. Army undertake defoliation trials for use against guerrilla forces, and in 1961 and 1962 chemical agents were shipped to the Vietnamese military. These studies, in addition to those conducted in the United States, showed both that the esters of 2,4-D plus 2,4,5-T readily defoliated woody vegetation and that cacodylic acid showed promise as a fast-acting desiccant. Several thousand chemicals were tested by the U.S. Army, industry, state agricultural experiment stations, U.S. Department of Agriculture (USDA), and others for either military or agricultural use. Few chemicals were more successful than the esters of 2,4-D plus 2,4,5-T against woody vegetation (Bovey, 1980c ). In addition to the phenoxys, a large body of information on picloram was also obtained concerning weed species controlled,
residues in the environment, safety, and physiological behavior in plants. Assistance by industry, private, state, and federal institutions, and Fort Detrick produced basic and practical infonnation for agriculture, as well as for military use (Bovey, l980b).
