Herbicidal Action of 2,4-Dichlorophenoxyacetic Acid on Several Shrubs, Vines, and Trees

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Abstract
Experiments were conducted in the immediate vicinity of Geneva, New York, between April 20 and July 25,1945, using several formulations of 2,4-dichlorphenoxyacetic acid as a herbicide applied as a water spray at concentrations of 1,000 and 2,000 ppm. to certain shrubs, vines, and trees. Conc, salves of these materials were also applied to cut surfaces. Application as a foliage spray at 2,000 ppm. during a warm period (80[degree]-85 [degree]F) in early Apr. resulted in death of chokecherry, honeysuckle, poison ivy, sumac, hawthorn, and elm after 3 weeks. No effect was observed on juniper. Applications as a foliage spray at 2,000 ppm. during a cool period (below 50[degree]F) in late Apr. resulted in marked reduction in response. Death of sumac, chokecherry, honeysuckle, hawthorn and elm did not occur until a warm sunny period in June. 50% of the poison ivy treated in late Apr. completely recovered. No effect was observed on juniper. Applications to cut surfaces in early spring in the form of cone, salves resulted in typical curvatures, browning, and necrosis of leaves, exudation of gum, proliferation of the inner bark, and death of the entire plant, provided sufficient active material was used on the cut surface. Application as a water spray in June at 1,000 and 2,000 ppm. resulted in death of the above ground parts of Virginia creeper, grape, willow, chokecherry, and honeysuckle. Application to hawthorn in June when the leaves were fully expanded and mature, resulted in blackening of the growing tips, but not death of the entire plant.