Antifungal Activity of Methanol Extracts Obtained from Verbascum L. (Mullein) Species Collected from Different Regions Against Rhizoctonia solani

Abstract

Plants are among the important natural resources preferred in combating plant pathogens due to their secondary metabolites. In this study, the antifungal effects of methanol extracts obtained from regional Verbascum (Mullein) species collected from ecologically different locations (Karasu, Konya, Bolu, Arifiye, and Manisa) were investigated under in vitro conditions against Rhizoctonia solani (J.G. Kühn), a soil-borne phytopathogenic fungus with a wide host range. For this purpose, methanol extracts were obtained from the flower and leaf parts of Verbascum species, and the potential of these extracts at different concentrations (0.5%, 1%, 2%, and 4%) to inhibit mycelial growth in the culture medium was evaluated. All tested extracts exhibited antifungal activity at varying levels. The extract prepared from samples collected in Konya showed the highest inhibition of mycelial growth, suppressing it by 55%. This was followed by the extract from Karasu with an inhibition rate of 45%. Extracts obtained from other locations exhibited antifungal activity at varying degrees, inhibiting mycelial growth between 7.5% and 36.25%. The findings indicate that methanol extracts obtained from Verbascum species exhibit antifungal activity against Rhizoctonia solani and that this effect increases with the applied dose. These results suggest that the active compounds present in Verbascum species should be identified and that their potential as alternative natural fungicides in biological control should be further supported by advanced research.