Propiconazole (Tilt®) was applied to Florunner peanut by injection into irrigation water (chemigation) or as a foliar spray. At rates of 0.12-0.25 kg/ha of propiconazole control of both Rhizoctonia limb rot (Rhizoctonia solani AG-4) and stem rot (Sclerotium rolfsii) was inconsistent. Chemigation resulted in the lowest incidence of stem rot, but the incidence of stem rot was only 26% less than the control. Yields from plots receiving chemigation were greater than expected based on disease ratings, indicating that some effects of the fungicide were not being evaluated. Where foliar sprays of chlorothalonil were applied for late leaf spot (Cercosporidium personatum), supplemental applications of propiconazole via chemigation improved leaf spot control. However, substituting chemigated propiconazole for foliar sprays of chlorothalonil consistently resulted in more severe leaf spot and, in one year, decreased yields. Propiconazole is most effective against leaf spot when applied as a foliar spray, whereas chemigation applications provide optimum efficacy against soilborne pathogens of peanut.