Exploitation of Various Crude Plant Extracts Against Black Scurf Disease of Potato in Saudi Arabia

Antifungal activities of five plant species (Thymus vulgaris, Lavandula vera, Menta viridis, Rosmarinus officinalis and Cassia italic) extracts were tested against Rhizoctonia solani using three different solvents (methanol, acetone and chloroform). Using linear growth technique, the percentages of growth inhibition caused by extracts were determined. The methanol extracts of all test plants were the most effective to inhibit the mycelial growth of test fungus. The percent of growth inhibition of R. solani was least affected by the chloroform extract. Whereas, at 8 % concentration, methanol extracts of R. officinalis and T. vulgaris caused complete (100 %) inhibition of R. solani growth. Similar results for M. viridis were attained only at 10 % concentration, compared to control treatment. The analysis of High performance liquid chromatography of five plants indicated that, the extraction with different solvents will lead to different types and concentrations of phenolic compounds.