Yellow nutsedge (Cyperus esculentus) control and peanut tolerance to S-metolachlor and diclosulam combinations

Field studies were conducted in different peanut-growing areas of Texas during the 1999 through 2001 growing seasons to evaluate yellow nutsedge control and peanut tolerance to diclosulam alone applied PRE, S-metolachlor alone applied POST, or diclosulam applied PRE followed by (fb) S-metolachlor applied POST. Yellow nutsedge control was > 80% at five of six locations when diclosulam at 0.018 or 0.026 kg/ha applied PRE was fb S-metolachlor applied POST at 0.56, 1.12, or 1.46 kg ai/ha. Peanut stunting was noted with diclosulam at the High Plains locations but not at the Rolling Plains or south Texas locations. This stunting with diclosulam was due to a combination of peanut variety and high soil pH. Peanut yield was not always increased where yellow nutsedge was controlled.