The aim of this study was to assess in vitro, the antifungal activity and characterize the chemical constituents of the essential oils of Azadirachta indica (neem) and Lavandula angustifolia (lavender). The essential oils of A. indica and L. angustifolia plants were tested against several isolates of pathogenic fungal genera causing root rot disease of ginseng. Agar plate assay indicated that lavender oil at 10% exhibited the highest inhibition index of (86.0±0.7%) against Sclerotinia nivalis mycelial growth. Neem and lavender oils at 5% v/v showed inhibition index against Alternaria panax (72.9±2.1 and 45.0±1%, respectively). Lavender oil at 5% (v/v) inhibited growth of S. nivalis (83.1±0.2%) and Cylindrocarpon destructans (49.2±1%). The gas chromatography-mass spectrometry (GC-MS) analysis showed that the major constituents of neem oil were fatty acids (94.8%). However, sesquiterpenes were the dominant constituents of the lavender oil (57.6%). The antifungal indices demonstrated in this study are a clear evidence of the potentiality of neem and lavender essential oils to control plant diseases caused by phytopathogenic fungi.
Key words: Ginseng root rot, fungi, essential oils.