Weed control in soybean (Glycine max) with cloransulam and diclosulam

Field studies were conducted in 1997 and 1998 to evaluate weed control and soybean (Glycine max) yield with cloransulam and diclosulam. Cloransulam at 35 g/ha applied preplant incorporated (PPI) and preemergence (PRE) control led at least 91% of hyssop spurge (Euphorbia hyssopifolia) and prickly sida (Sida spinosa) and at least 82% of entireleaf morningglory (Ipomoea hedera cea var. integriuscula) and pitted morningglory (Ipomoea lacunosa) at 7 wk after planting. Control of these species with cloransulam was not affected by method of soil application. Control of prickly sida with cloransulam PPI or PRE was better than with cloransulam postemergence (POST) at 18 g/ha. S oybean yields were similar with cloransulam PPI (2,880 kg/ha) or PRE (3,110 kg/ka) and were comparable to imazaquin PRE at 140 g/ha (3,080 kg/ha). Wee d control and soybean yields with cloransulam POST were similar to that wit h chlorimuron POST at 11 g/ha. SAN 582 plus cloransulam PRE followed by clo ransulam POST provided the highest soybean yield (3,450 kg/ha). Diclosulam PPI or PRE provided similar levels; of control of hyssop spurge, Ipomoea mo rningglories, and prickly sida. Overall, control of these species with dicl osulam PPI or PRE was similar to that obtained with sulfentrazone plus chlo rimuron PRE. Soybean yields (greater than or equal to 3,290 kg/ha) were sim ilar regardless of method of diclosulam application, and yields were equiva lent to that of sulfentrazone plus chlorimuron PRE (3,270 kg/ha).