Sixteen fungal isolates were recovered from infected peanut seeds on blotter and potato dextrose agar (PDA) medium. Among these isolates, Sclerotium rolfsii recorded the highest percentage on infected seeds. Seven essential oils of plant origin were evaluated for their action on the suppression of S. rolfsii. These oils were cinnamon oil, basil oil, lemon grass, tea oil, spearmint oil, mustard oil, and thyme oil. There was a reduction in the mycelium linear growth by increasing the oils concentrations. All the tested oils inhibited the sclerotial germination but at different concentrations. Higher concentrations of oils had an inhibitive effect while lower concentrations had a static action on the mycelial growth as well as sclerotial germination of S. rolfsii. Two concentrations for each of the 7 tested oils were tested for their effect on the development of the disease from infected seeds. Results revealed that basil and thyme oils at 2% caused 100% suppression of the fungal infection.  Scanning electron microscopy of S. rolfsii treated with thyme oil showed that the volatile toxic compounds of the oil had a negative effect on the mycelium and the structure of sclerotia of seed-borne S. rolfsii.