Prickly Sida (Sida spinosa L.), Hemp Sesbania [Sesbania herbacea (Mill.) McVaugh], and Pitted Morningglory (Ipomoea lacunose L.) Response to Selective and Non-Selective Herbicide in Mississippi, USA

Prickly sida (Sida spinosa), hemp sesbania (Sesbania herbacea), and pitted morningglory (Ipomoea lacunose) are becoming problematic weeds in many crops including corn and soybean. Two separate field experiments, under non-crop conditions, were conducted at the Mississippi State University Delta Research and Extension Center, in Stoneville, MS to evaluate the response of these weeds to eight corn selective herbicides and three non-selective herbicides alone or in combination. The herbicides used were Aatrex (atrazine), Clarity (dicamba), 2,4-D (2,4-D amine), Callisto (mesotrione), Enlist Duo (2,4-D choline + dicamba), Capreno (thiencarbazone + tembotrione), Corvus (thiencarbazone + isoxaflutole), Halex GT (mesotrione + S-metolachlor + glyphosate), Gramoxone (paraquat), Liberty (glufosinate), and Roundup (glyphosate). Halex GT provided only 86% prickly side control 4-wks after application (WAA). Aatrex + Capreno and Aatrex + Corvus were the only treatments provided 99.5% prickly sida control. Liberty, Callisto, Capreno, and Corvus provided 71, 66, and 51, and 46% control of prickly sida, respectively. Hemp sesbania control was 100% from all herbicide applications except Corvus and Roundup. Hemp sesbania control was not satisfactory from Roundup application since this treatment provided only 72% control. By 4 WAA, all herbicide treatments provided 97 to 100% on pitted morningglory control except Corvus and Capreno treatments (72 to 75%). The herbicide management program should be able to provide acceptable weed control (i.e., greater than 95%) but also to prevent weed seed deposition onto the soil seedbank. Consequently, delaying the evolution of weed herbicide resistance will result in herbicide technology preservation for as long as possible by achieving a long-term weed management program.