Streamline Basal Application of Herbicide for Small-Stem Hardwood Control

Abstract

Abstract The effectiveness of low-volume basal application of herbicide—"streamline" application—was evaluated on 25 hardwood species and loblolly pine. Test mixtures were step-wise rates of Garlon 4 mixed in diesel fuel with a penetrant added. Most comparisons tested 10%, 20%, and 30% mixtures of Garlon 4, while tests with saplings and small trees used 20%, 30%, and 40%. Target stems ranged from 2 ft tall to 6 in. dbh. Applications were made in February, using pressure-regulated handguns equipped with straight stream nozzles attached to backpack sprayers. Two bands of the herbicide mixture were applied to two sides of all stems. After 18 months, susceptible hardwood species with greater than 80% average control at all three Garlon rates were water oak (Quercus nigra), am. hornbeam (Carpinus caroliniana), black locust (Robinia pseudoacacia), boxelder (Acer negundo), huckleberry (Vaccinium elliottii), sumacs (Rhus spp.), southern bayberry (Myrica cerifera), and mountain-laurel (Kalmia latifolia). Tolerant species with less than 40% control were sourwood (Oxydendrum arboreum), titi (Cliftonia monophylia), and yellow poplar (Liriodendron tulipifera) (>1 in. groundline diameter). Treatment of loblolly pines resulted in an average of 22% mortality. Smaller stems were more readily killed than larger stems for all species. South. J. Appl. For. 14(4):161-165.