Effect of Additives upon Phenmedipham for Weed Control in Sugarbeets

Weed control and sugarbeet ( Beta vulgaris L.) injury from applications of methyl m -hydroxycarbanilate m -methyl-carbanilate (phenmedipham) were influenced by additives, volume of additive, and species in both field and greenhouse experiments. Oils were more effective than the surfactant as additives to phenmedipham on green foxtail ( Setaria virdis (L.) Beauv.), yellow foxtail ( Setaria glauca (L.) Beauv.), redroot pigweed ( Amaranthus retroflexus L.), or common lambsquarters ( Chenopodium album L.). Herbicidal activity of phenmedipham on kochia ( Kochia scoparia (L.) Schrad.) or wild mustard ( Brassica kaber (D.C.) L.C. Wheeler var. pinnatifida (Stokes) L.C. Wheeler) was not enhanced by any additive. Linseed oil (2.34 L/ha) enhanced the herbicidal activity of phenmedipham on green foxtail, yellow foxtail, and redroot pigweed more than petroleum (2.34 L/ha) or sunflower ( Helianthus annus L.) oil (2.34 or 9.35 L/ha). However, linseed oil reduced the herbicidal activity of phenmedipham on kochia.