Preemergence and Postemergence Yellow Nutsedge (Cyperus esculentus) Control with MON 12000 in Nursery Crops

Abstract

Yellow nutsedge is a common and troublesome weed in the nursery industry. A selective postemergence herbicide is not available for yellow nutsedge control in most nursery crops. The effectiveness of MON 12000 for PRE and POST control of yellow nutsedge was evaluated in selected field-grown nursery crops. Preemergence control of yellow nutsedge 4 weeks after treatment (WAT) increased from 68% to 95% as MON 12000 rate increased from 0.03 to 0.28 kg ai/ha. At 9 WAT, control ranged from 16 to 73%. MON 12000 at 0.14 kg/ha provided similar PRE control of yellow nutsedge as metolachlor at 2.2 kg/ha. Four WAT, MON 12000 applied POST at 0.03 kg/ha controlled 73% and controlled 86% with the 0.28 kg/ha rate. MON 12000 at 0.14 and 0.28 kg/ha applied POST controlled yellow nutsedge better than bentazon at 1.12, chlorimuron at 0.01, imazaquin at 0.14, or glyphosate at 3.33 kg/ha. MON 12000 injured the foliage of azalea, crape myrtle, cotoneaster, and Japanese holly. Injury was most severe to cotoneaster. MON 12000 reduced azalea, cotoneaster, and crape myrtle shoot fresh weight compared to hand-weeded plots in at least one study. Metolachlor at 2.2 and 4.5 kg/ha caused little injury to the nursery species tested.