Large-scale use of plant growth-regulating chemicals, unheard of ten years ago, has fostered a multimillion dollar business. In 1948, 27 1/2 million pounds of 2,4-D, once used only in minute doses for laboratory work, were manufactured for agricultural use, primarily in weed eradication. Naphthaleneacetic acid and other compounds are used in smaller but continually increasing quantities in regulating other phases of plant development, wholly apart from nutritional needs supplied by fertilizers.