Influence of Foam Adjuvants on Activity of Selected Herbicides

Abstract

Three blended foam adjuvants increased 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] uptake from aqueous solutions by detached live oak (Quercus virginianaMill.) leaves as compared to uptake from water alone. There were no differences in honey mesquite [Prosopis juliflora(Swartz.) D.C. var.glandulosa(Torr.) Cockerell] control with 2,4,5-T or 1:1 combinations of 2,4,5-T with picloram (4-amino-3,5,6-trichloropicolinic acid) or with dicamba (3,6-dichloro-o-anisic acid) at 0.56 kg/ha whether applied in water + 0.5% (v/v) foam adjuvant or in a diesel oil: water (1:4, v/v) emulsion. Residual life of picloram in native forages was not extended by foam carrier as compared to water, water and surfactant, and diesel oil:water emulsion as carrier. Foam generation from adjuvants with expansion ratios (ER) of two to four was less susceptible to alteration from addition of commercially-formulated herbicides than was an adjuvant with an ER of seven. Foam adjuvant ER's increased in a curvilinear fashion as water temperature was increased from 5 to 50 C.

Foliar Uptake and Transport of 2,4-D and Picloram by Drummond's Goldenweed (Isocoma drummondii)

“…Least detectable concentrations were less than 0.01 jUg/g for both herbicides. Herbicide uptake in field experiments is given as the ratio of the amount of herbicide detected in leaf tissues to the total amount of herbicide recovered from within and on leaves, expressed as a percentage (5,18).…”