Influence of Adjuvants on the Deposition, Absorption, and Translocation of Clopyralid in Honey Mesquite (<i>Prosopis glandulosa</i>)

Abstract

The addition of surfactant (trimethylnonylpolyethoxyethanol) at 0.5% (v/v) of the spray solution caused a twofold increase in the deposit of clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) applied at 0.14 or 0.28 kg ae/ha on greenhouse-grown honey mesquite ( Prosopis glandulosa Torr. # PRCJG) and increased transport into the plants compared to clopyralid applied alone. Application of equal rates of benazolin [4-chloro-2-oxo-3(2 H )-benzothiazoleacetic acid] with clopyralid at 0.28 + 0.28 kg/ha enhanced transport of clopyralid into honey mesquite. Spray deposit, absorption, and translocation of clopyralid was unaffected by addition of 0.5% (v/v) of d'limonene (4-isopropenyl-1-methyl-cyclohexane). Greater spray deposit of clopyralid on plant surfaces after addition of surfactant was associated with reduced liquid surface tension and greater percentage of spray volume in small droplets (&lt;204-μm diam).