Absorption, translocation, and phytotoxicity of dicamba and glyphosate in woollyleaf bursage (Franseria tomentosa Gray)

Permanent control of deep-rooted perennial weeds is essential in most crop production systems in order to eliminate competition and maintain a higher potential for productivity. However, perennial species exist for which herbicidal control is currently ineffective or economically unfeasible. Dicamba (3,6-dichloro-o-anisic acid) and glyphosate [N-(phosphonomethyl)glycine] are two herbicides used as postemergence treatments that have proven to be effective in controlling various perennial weeds. Efficacy of these two herbicides is often dependent upon certain factors including growth stage at the time of application, degree of foliar penetration, and ultimately the extent of translocation to underground perennating organs (1,9,11,18,23).