Evaluation of Various Pre-emergent and Post-emergent Herbicides on Five Summer Legumes

Abstract

Currently there is little information regarding weed control in legumes; therefore, the effects of 16 pre-emergent and 12 post-emergent herbicide treatments were evaluated on five summer legumes during the 2005, 2006, and 2007 seasons. Pre-emergent herbicides generally did not improve legume yield, except for imazethapyr (Pursuit/Newpath) on Korean lespedeza. Post-emergent application of 2,4-DB (Butryrac) provided 94 to 97% control of woolly croton (Croton capitatus Michx.) but no control of pigweed (Amaranthus sp.), and it caused excessive injury to these legumes, except for Korean lespedeza. Fluazifop (Fusilade), sethoxydim (PoastPlus), and clethodim (Select) applied post-emergent provided the greatest large crabgrass [Digitaria sanguinalis (L.) Scop] control (91, 91, and 94%, respectively) and did not injure any of the legumes. Imazethapyr and imazamox (Raptor) provided moderate (63 to 72%) woolly croton control with little legume injury. Imazapic (Plateau/Impose) and imazapic-glyphosate (Journey) produced moderate visual injury ratings for all forage legume species (17 to 32%) and provided good woolly croton control (82%) and moderate large crabgrass (43 to 59%) and pigweed (45%) control. Therefore, imazethapyr, imazamox, and imazapic have the greatest potential for improving yield and quality of these summer legumes.