ABSTRACT
Picloram (4-amino-3,5,6-trichloropicolinic acid) is a new herbicide known by the trademark Tordon®. It has shown wide spread promise for the control of many woody plant species, as well as herbaceous perennial weeds by conventional foliage sprays. The treatments were applied with a small, compressed-air sprayer equipped with a narrow angle cone nozzle. Chemical treatments were applied immediately after cutting the frills with a hand axe. Single-stem white oak trees (Quercus alba L.), ranging in size from 5 to 10 in. in diameter at 5-ft height, were treated in April. Treatments applied to frills made half way around the tree and on one side only were relatively ineffective, regardless of chemical or frill position. An attempt was made to determine the minimum amount of Tordon® required per injection with injections spaced on 3-in. centers around the base of hardwood trees.
