Influence of Time and Method of Application on Turkey Oak Response to Picloram + 2,4-D

Abstract

Naturally-established turkey oak (Quercus laevis Walt.) shoots were treated with aqueous solutions of the product picloram + 2,4-D (4-amino-3,5,6-trichloropicolinic acid + 2,4-dichlorophenoxyacetic acid) and with picloram pellets. Various application methods were utilized at several dates during the year. Responses measured 14 and 17 months after initial treatments were percent control of original shoots, percent regrowth, plant height, and live stems/plant. Leaf-stem-basal treatments provided the highest degree of control of any method studied, averaging 87% total shoot control over five treatments dates. Foliar, mist-blower, and leaf-stem applications showed no differences, averaging 75%, 79%, and 78% control, respectively. Basal applications gave poorest results averaging only 12% control over five dates. No differences were observed among treatment dates for applications made during the growing season after the full-leaf stage, but treatments made before full-leaf provided less control than others. Soil applications of picloram pellets were more effective when applied during the early spring and summer than during fall or winter but were less effective than treatments applied to foliage at all dates.