Influence of vegetable and mineral oils on the efficacy of some post-emergence herbicides for grass weed control in wheat

Two field experiments in central Italy on wheat showed that the application rate of clodinafop-propargyl could be significantly reduced to 1/2 of the labelled rate to control oats and canarygrass, with no loss in weed control efficacy. This reduction was favoured by the use of mineral or vegetable oil, with no apparent differences. No rate reduction of clodinafop-propargyl was possible for ryegrass, which needed at least the labelled rate plus vegetable or mineral oil to be satisfactorily controlled. A mixture of diclofop-methyl+fenoxaprop-p-ethyl could be effectively used only against oats controlled at 2/3 of the labelled rate. This mixture did not prove effective against canarygrass, while it was effective against ryegrass only when applied at the maximum labelled rate mixed with vegetable or mineral oil. (c) Pesticide Science Society of Japan.