Influence of Application Rate and Timing of Diclosulam on Weed Control in Peanut (Arachis hypogaea L.)

Abstract

Abstract Field studies were conducted from 1996 to 1998 in Georgia to determine peanut (Arachis hypogaea L.) and weed response to ethalfluralin (0.8 kg ai/ha) plus diclosulam applied preplant incorporated (PPI) at 9, 18, 26, 35 and 52 g ai/ha. Other treatments included ethalfluralin PPI followed by paraquat plus bentazon (140 and 280 g ai/ha, respectively) early postemergence (EPOST) applied alone or following ethalfluralin plus diclosulam (18 and 26 g ai/ha) PPI, ethalfluralin PPI followed by imazapic (71 g ai/ha) postemergence (POST), and ethalfluralin PPI. Ethalfluralin was applied PPI in all herbicide programs. Diclosulam controlled Florida beggarweed [Desmodium tortuosum (Sweet) D.C.], sicklepod [Senna obtusifolia (L.) Irwin and Barneby], and yellow nutsedge (Cyperus esculentus L.) inconsistently, and POST application of paraquat plus bentazon was needed for acceptable control. However, diclosulam controlled common ragweed (Ambrosia artemisiifolia L.), tropic croton (Croton glandulosus Muell-Arg.), wild poinsettia (Euphorbia heterophylla L.), and prickly sida (Sida spinosa L.) without the need for POST herbicides. Higher yields were recorded with diclosulam PPI followed by a sequential application of paraquat plus bentazon than herbicide programs not containing diclosulam or diclosulam alone. Diclosulam PPI followed by sequential applications of paraquat plus bentazon provided greater control of sicklepod and prickly sida that resulted in greater yields. Yields from dicosulam PPI followed by paraquat plus bentazon EPOST were equivalent to yields with paraquat plus bentazon EPOST followed by imazapic POST or imazapic EPOST.