Evaluation of inhibitory effects of some Iranian plants against Phytophthora drechsleri

Crude aqueous and methanolic extracts of 121 plant species belonging to 41 families collected from the west of Iran were screened for antifungal activity against mycelial growth of Phytophthora drechsleri. Bioassay was performed based on paper disc diffusion method with four replicates. Thirty eight of 121 (about 31%) plant species showed inhibitory activity against this phytopathogenic fungus, among which 23 species measurably inhibited the growth of Phytophthora drechsleri. Results indicated that methanolic extract of Xanthium strumarium L. showed the maximum activity (17.79±1.35mm) against P.drechsleri followed by Glycyrrhiza glabra L., Hypericum perforatum L., Centaurea depressa M.Bieb., Lamium amplexicaule L., Haplophyllum perforatum (M.B.) Vved. The investigation on the effect of plant parts on mycelial inhibition of tested fungus using paper disc method indicated that inflorescence and fruits of cocklebur (Xanthium strumarium) has significantly more inhibitory effect against P. drechsleri. The study on the antifungal activity of two common species of cocklebur grown around city of Kermanshah, X. strumarium and X. spinosum L., showed that both of them have inhibition on mycelial growth of tested fungus, but the X. strumarium showed significantly more inhibitory effect against P. dreschleri than X. spinosa.

Keywords: Phytophthora activity, Xanthium strumarium, Iranian plants, Paper disc

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