Influence of Adjuvants on Efficacy of Postemergence Herbicides Commonly Used in Peanut (Arachis hypogaea L.)

Abstract

Field studies were conducted for 2 years in the High Plains of Texas (34.1826 o N, 101.9505 o W) and in South Texas (29.1634 o N, 97.0725 o W) to evaluate weed control when using different adjuvants with commonly used peanut herbicides. In the High Plains, Amaranthus palmeri L. control with acifluorfen, imazapic, lactofen, and 2,4-DB at the 1X dose improved with the use of an adjuvant over no adjuvant. A. palmeri control with imazethapyr was similar to that seen with imazapic and lactofen with the exception of the 1/2X rate of imazethapyr, which showed improved control with Agridex over the use of no adjuvant or Induce in 1 year, while Induce was better than no adjuvant or Agridex in the other year. In 1 year in South Texas, A. palmeri control with imazapic at the 1X dose was ≥73% with/without an adjuvant. In another year, the 1X dose of imazapic controlled A. palmeri 64% without an adjuvant, while the addition of Cide Kick II resulted in 83% control. An adjuvant did not improve A. palmeri control with lactofen or Cucumis melo L. control with either imazapic or lactofen. Urochloa texana (Buckl.) control with clethodim at the 1X dose was not improved by the addition of an adjuvant in either year. U. texana control was not improved when using the 1X dose of fluazifop-P with any adjuvant.