New Formulation of Clethodim/Adjuvant at Control of Grass Weeds for Soybean Crops

Abstract

The use of ACCase-inhibiting herbicides without the correct addition of an adjuvant is a major cause of inefficient poaceous weed control. As such, this study aimed to assess the efficiency of a new clethodim/adjuvant formulated mixture in postemergence weed control for soybean crops. Two field experiments were conducted in the 2015/16 and 2016/17 growing seasons. A randomized block design, consisting of ten treatments with four repetitions, was used. The treatments and doses were: clethodim (108 g a.i. ha-1) + Lanzar® (0.5%), clethodim (108 g a.i. ha-1) + Nimbus® (0.5%), clethodim/adjuvant formulation at doses of (84 g a.i. ha-1), (96 g a.i. ha-1), (108 g a.i. ha-1), (120 g a.i. ha-1), (132 g a.i. ha-1), and (144 g a.i. ha-1), and a control with and without weeding. The formulated clethodim/adjuvant mixture showed high control at 7 days after application (DAA) in the 2015/16 growing season. At 28 DAA, formulation doses of 108 g a.i. ha-1 and higher exhibited superior weed control and the highest crop yields. Therefore, the use of correct adjuvant or formulated mixture is essential to increase the efficiency of clethodim herbicide.