The objective of this study was to determine if band width and timing affected the insecticidal and fungitoxic activity of chlorpyrifos granules applied to irrigated peanut. At two locations and in 3 yr, chlorpyrifos granules were applied to flowering-stage or pegging-stage peanuts of the cultivar Florunner through a drop-tube or in 23-cm or 46-cm-wide bands centered over the row. At midseason, all chlorpyrifos treatments, except the widest band width applied at pegging significantly reduced the incidence of stem rot, but no differences were found at harvest. Wireworm populations were highly variable among tests but, when numbers were sufficient for evaluation, all chlorpyrifos treatments reduced wireworm populations and numbers of damaged pods. Application method and timing had little effect on the efficacy of chlorpyrifos as an insecticide. Even though all chlorpyrifos treatments reduced-wireworm damage to peanut pods and at least delayed the onset of stem rot, only the drop-tube application at flowering resulted in increased yield at one location. Orthogonal contrasts of flowering-stage applications versus pegging-stage applications indicated that the flowering-stage applications resulted in higher yields and values per hectare.