"In 1945, the American Chemical Paint Company introduced its product Weedone, the first herbicide ever to hit the market that killed broad-leaved plants but not grasses. On farms, the weedkiller reduced the need for pulling weeds in grain fields, a godsend during the post-war labor shortage.
At home, Weedone killed dandelions, clover, plantain and other “weeds,” leaving turfgrasses uninjured. A uniform, weed-free lawn was at last within reach of the average household.
The active ingredient in Weedone was a compound called 2,4-Dichlorophenoxyacetic acid, 2,4-D for short. It had been developed by several separate teams of researchers working on secret chemical weapons projects during the war; the generals hoped to use 2,4-D to kill potato and rice crops, starving the Axis powers into submission."