Antifungal activity of nine plant extracts on tobacco Sore Shin disease (Rhizoctonia solani)
Tobacco Sore Shin disease، Rhizoctonia solani is one of the important agent with worldwide and causes yield losses in tobacco growing countries. This research has conducted with two targets، the study of antifungal activity of plant extracts on this pathogen and screened the best solvent to extract. In this study، crude extracts of 9 plant species including: Catmint (Nepeta Cataria)، tobacco (Nicotiana tabacum)، thyme (Thymus pubescens)، Fennel (Foeniculum vulgar)، Nepeta (Mentha pulegium)، hyssop (Hyssopus officinalis)، Blam (Melissa angustifolious)، Salvia (Salvia verticilata) and Badrashbi (Dracocephalum kotschyi) by using solvents، water، acetone، hexane، ethanol، and methanol were obtained. Antifungal activity of this compound، were tested using poisoned food method with concenterations of 0. 1000 and 2000 ppm invitro landifious. Results indicated that crude extracts of Tobacco، Catmint، Thyme، Fennel، Hyssop and badrashbi have remarkable antifungal activity. Methanol was the best solvent to extract these compounds. Minimum inhibitory concentration of methanol extract of Tobacco، Catmint، Thyme، Fennel، badrashbi، and Hyssop were equal to 1. 5، 1. 5، 2، 3، 3، and 2. 5 mg/ml، respectively when on this fungal pathogens. Therefore، it is likely possible to use plant extracts of these plants، especially N. cataria، N. tabacum and T. pubescens، for the control of tobacco sore shine disease.