Acephate, carbaryl, cypermethrin, fenvalerate, permethrin and methidathion applied as foliar sprays were evaluated in the field for crop protection against the potato leafhopper, Empoasca fabae (Harris), infesting valencia peanuts, Arachis hypogaea L., in Ontario. All of the insecticides significantly suppressed nymphal populations and the results obtained were consistent over the 3 years. The residual toxicity of each material at the rates applied was discussed. Sampling data demonstrated that monitoring of nymphs can be used successfully to schedule insecticidal sprays for control of this pest on peanuts grown commercially in Ontario.