Field studies were conducted from 2000 to 2002 to evaluate yellow nutsedge control and peanut yield when diclosulam and imazapic were applied at the rate recommended by the manufacturer (1×) and reduced (1/2×) rates in single and twin-row planting patterns. In 2001, both diclosulam and imazapic applied to the twin-row pattern at the full and reduced rate provided better yellow nutsedge control than herbicide applications to the single-row spacing. Because of excessive rainfall in 2002, yellow nutsedge control was considerably reduced with all treatments. Imazapic at the full rate (71 g/ha) controlled yellow nutsedge 80 to 96% in the twin-row pattern, and 79 to 86% in single-row spacings. Yellow nutsedge control was less than 65% when diclosulam and imazapic were applied at the reduced rate. The twin-row configuration yielded higher than the single-row pattern when averaged across herbicides in 1 yr. All herbicide treatments enhanced yield relative to the nontreated control, except the reduced rate of imazapic in 2002. This study revealed that to fully maximize yellow nutsedge control, the full rate of either imazapic or diclosulam should be applied to peanuts planted in a single or twin-row spacing. However, these treatments may not necessarily increase peanut yields.

Nomenclature: Diclosulam; imazapic; yellow nutsedge, Cyperus esculentus L. CYPES; peanut, Arachis hypogaea L. ‘Georgia Green’