Redroot Pigweed (Amaranthus retroflexus) Control with Bentazon plus Additives

A water-soluble linseed oil formulation was compared with emulsifiable linseed oil as an additive to bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide] for redroot pigweed (Amaranthus retroflexus L.) control. A water-soluble linseed oil formulation as an additive to bentazon controlled redroot pigweed better than did an emulsifiable linseed oil additive. Further, the water-soluble linseed oil additive enhanced redroot pigweed control with bentazon more than the emulsifiable linseed oil when a simulated rainfall followed application, or when humidity was low (30 to 45%) or spray volume high (170 to 340 L/ha). Redroot pigweed control with bentazon plus the water-soluble linseed oil additive followed by simulated rainfall in 4 h was similar to control with bentazon applied alone without a simulated rainfall.