Published online by Cambridge University Press: 12 June 2017
Purple nutsedge (Cyperus rotundus L.) control with (2,4-dichlorophenoxy)acetic acid (2,4-D) and 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) was increased in greenhouse and growth chamber studies by application of these herbicides in an undiluted isoparaffinic oil carrier rather than water. Two applications of 2,4-D at 2.2 kg/ha in the oil carrier inhibited tuber and shoot production and reduced the number of viable tubers present, but two applications of linuron at 0.6 or 2.2 kg/ha in the oil inhibited only shoot production from repotted tubers. Studies with labeled 2,4-D showed an increase in both rate and quantity of penetration of this herbicide into purple nutsedge when applied in oil rather than water. Labeled linuron was applied to purple nutsedge and to beans (Phaseolus vulgaris L. ‘Improved Tendergreen’) and also showed an increase in penetration with the oil rather than water. Translocation out of treated leaves was not increased for either 2,4-D or linuron by application in the oil carrier.