Inhibitory effectof essential oils and ethanol extractsof watermint (Mentha aquatica) against some plant pathogenic fungi in laboratory condition

In recent years studies on the use of plant essential oils and extracts against pathogenic fungi have attracted much attention because of rising resistance against a large number of chemical pesticides. Essential oils are antifungal materials which are renewable and compatible with environment. In this study, essential oil and ethanol extracts of watermint (Mentha aquatica) were obtained from aerial parts using distillation and ethanol solvent methods, respectively. The inhibitory effect of different concentrations (0, 100, 200 and 300 ppm / 9 cm Petri dish) of watermint essential oilswith fumigation and contact methods and their extracts on mycelium growth of Botrytis cinerea, Fusarium oxysporum, Rhizoctonia solani, Phytophthora capsici were investigated in a factorial experiment based on completely randomized design. Fungi showed different sensitivity to watermint essential oils and extract. None of watermint concentrations of essential oils and extract had any inhibitory effect on growth of F. oxysporum but all concentrations inhibited the growth of B. cinerea, R. solani and P. capsici significantly. Increase in concentration enhanced the inhibitory effect significantly. The highest percentage of inhibition was related to concentrations 200 ppm and 300 ppm in R. solani (%91.06 and %97.77 respectively) and also concentration 300 ppm in P. capsici (%91.89). Therefore, watermint essential oils and extract can be considered as natural fungicide for control of pathogenic fungi.