Sicklepod (Senna obtusifolia) and Entireleaf Morningglory (Ipomoea hederaceavar.integriuscula) Management in Soybean (Glycine max) with Flumetsulam

Systems consisting of flumetsulam, metribuzin plus chlorimuron, or imazaquin applied PPI with trifluralin or PRE with metolachlor were compared with and without chlorimuron POST for control of sicklepod and entireleaf morningglory in narrow-row soybean at four locations. Control of sicklepod and entireleaf morningglory by soil-applied herbicides was generally inadequate. Control of sicklepod by flumetsulam exceeded control by metribuzin plus chlorimuron or imazaquin at one location. Entireleaf morningglory control by flumetsulam was similar to or less than control by metribuzin plus chlorimuron or imazaquin. Chlorimuron POST was a more important component of management systems for these weeds than was flumetsulam, metribuzin plus chlorimuron, or imazaquin PPI or PRE. Pooled over soil-applied herbicides, chlorimuron POST increased late-season control of sicklepod and entireleaf morningglory 25 to 61% and 22 to 54%, respectively; increased soybean yield 20 to 55%; decreased foreign matter contamination 5 to 13%; and increased net returns $34 to $185/ha. When used in conjunction with chlorimuron POST, flumetsulam, metribuzin plus chlorimuron, and imazaquin applied PPI with trifluralin or PRE with metolachlor increased late-season control of sicklepod and entireleaf morningglory only when control by trifluralin or metolachlor followed by chlorimuron POST was less than 66 and 77%, respectively.