Antifungal effects of some medicinal and aromatic plant essential oils against Alternaria solani

In this study, anti Alternaria solani effects of essential oils of 11 medicinal and aromatic plant species belonging to four families collected from the west of Iran were investigated based on agar dilution method with five replications at concentration of 1.0 μl/ml. The results showed that the highest inhibitory effect belonged to Oliveria decumbens, Cinnamomum zeylanicum, Carum copticum and Thymus kotschyanus which completely inhibited the mycelial growth of the fungus. Therefore, their activity was examined in lower concentrations, too. The essential oil of O. decumbens at concentration of 0.50 and 0.25 μl/ml completely suppressed the mycelial growth of the fungus. The major constituents of its essential oil were carvacrol (46.53%), thymol (23.75%), p-Cymene (13.70%), γ-terpinene (7.66%) and myristicin (3.65%), respectively. Thus, the essential oil of this species with the highest anti-Alternaria activity could be selected for further studies on in vivo application as natural fungicide.