The discovery of the first systemic or hormone herbicides, 2,4-D, 2,4,5-T, and MCPA, initiated an agricultural revolution and modern weed science. The finding of these herbicides was a striking case of multiple independent discovery by four groups of workers in two countries, the United Kingdom and the United States: William G. Templeman and associates at Imperial Chemical Industries; Philip S. Nutman and associates at the Rothamsted Agricultural Experiment Station; Franklin D. Jones at the American Chemical Paint Company; and Ezra Kraus, John Mitchell, and associates at the University of Chicago and the U.S. Department of Agriculture. Because of wartime and commercial secrecy, the usual procedures of scientific publication and patent disclosure were not followed; instead, the first scientific report on these herbicides occurred in a publication by workers who were not original discoverers. Considerable confusion consequently resulted concerning the discovery and the discoverers. This confusion has not been completely dispelled in subsequent years. The present report summarizes the complete story, clarifies the chronology of the discoverers and their publications, and makes the case that all four groups of workers deserve credit for this revolutionary advance. The scientific background of the discovery and events in its immediate aftermath, especially the ticklish patent situation, are also briefly chronicled.

Nomenclature: 2,4-D; MCPA; 2,4,5-T.