Ability of Adjuvants in Enhancing the Performance of Pinoxaden and Clodinafop Propargyl Herbicides Against Grass Weeds

Adjutant's ability in enhancing the performance of herbicides is a major priority in adjuvant research. To identify an appropriate adjuvant for pinoxaden and clodinafop propargyl herbicides against littleseed canarygrass (Phalaris minor Retz.), common wild oat (Avena fatua L.) and ryegrass (Lolium temulentum L.), three separate experiments were conducted under greenhouse conditions. In all experiments treatments consisted of five doses of pinoxaden and two doses of each of the three commercial formulations of clodinafop propargyl (Topik, Behpik & Karent), with and without the adjuvants Adigor, Citogate, Citohef and Volk. Performance of all herbicides increased with enhancing their concentrations against the tested plants except for clodinafop propargyl in case of wild oat. The addition of Volk (followed by Adigor) had the highest effect on pinoxaden efficacy against ryegrass and littleseed canarygrass, supporting the idea that either Volk or Adigor solubilizes the cuticular waxes thus facilitating their uptake. Adding Volk and Adigor had the highest and lowest influence on pinoxaden performance against wild oat, respectively. Totally, the adjuvant receptivity for pinoxaden was higher than for clodinafop propargyl. Between the two surfactants, Citogate was more effective than Citohef in enhancing the efficacy of pinoxaden against ryegrass and littleseed canarygrass, while, Citohef was more effective in increasing the efficacy of pinoxaden against wild oat.