Comparison of Metolachlor and Dimethenamid for Yellow Nutsedge (Cyperus esculentus L.) Control and Peanut (Arachis hypogaea L.) Injury1

Abstract

Abstract Field experiments were conducted during 1996 and 1997 at four locations in Texas to evaluate metolachlor and dimethenamid for yellow nutsedge (Cyperus esculentus L.) control and peanut (Arachis hypogaea L.) injury. Dimethenamid and metolachlor were applied PPI or PRE at 0.6X to 2x the suggested label rates. Yellow nutsedge failed to develop at one location; however, early season yellow nutsedge control with dimethenamid and metolachlor were similar at one location, and at two other locations metolachlor provided greater nutsedge control than dimethenamid. Furthermore, late season yellow nutsedge control at the three locations was better with metolachlor than dimethenamid. Peanut stunting was 20% higher with metolachlor PRE at the 1x rate than dimethenamid PRE at the 1x rate at two locations when rated 4 or 12 wk after treatment (WAT). Peanut yields were variable but, at one location under weed-free conditions, plots receiving pendimethalin only had the highest yield. With excessive moisture and herbicide rates greater than recommended for field use, both dimethenamid and metolachlor caused peanut stunting. However, metolachlor provided better season-long yellow nutsedge control than dimethenamid.