Period of Effective Weed Control by the Use of 2,4-Dichlorophenoxyacetic Acid

Abstract

The behavior of exptl. lawn grass plots treated with 2,4-D for 2 yrs. was studied. Plots sprayed with 500 or 1,000 ppm. of 2,4-D were almost free of dandelions 1 yr. later. There was no adverse effect on the growth of lawn grasses. Narrow-leaved plantain was excellently controlled by 125 to 250 ppm. of the acid. 2,4-D could be applied dry, together with various mineral and dry organic fertilizers so as to kill weeds and enrich the soil in 1 application. Control plots containing an avg. fresh wt. of 62.2 gm. of weeds, whereas plots receiving 11/2, 3, 6, and 9 lbs. per acre of 2,4-D in the fertilizer contained a fresh wt. of 7.4, 6, 2.4, and 1.8 gm. of weeds, respectively. Repeated sprayings were not harmful to established grasses.