Foliar sprays of 4-amino-3,4,5-trichloropicolinic acid (picloram) controlled winged elm (Ulmus alata Michx.) more effectively than 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). Picloram and 2,4,5-T in a mixture effectively controlled the elm. Sprays of 2,4,5-T with ammonium thiocyanate (NH4SCN) added, and a (1:1) combination of NH4SCN and 3-amino-1,2,4-triazole (amitrole) additive, controlled the elm. Foliar sprays of 2,4,5-T without additives have been relatively ineffective. Soil moisture shortage, followed by watering immediately after treatment of winged elm with 2,4,5-T-C14, increased the translocation of 2,4,5-T as compared to plants maintained in moist or dry soils.
Picloram controlled winged elm when applied with an injector or as a soil treatment. The 2,4,5-T diluted in diesel oil, applied as an injector treatment, effectively controlled winged elm.