3.1. Antifungal activities of essential oils on mycelial growth
The volatile and contact phase effects of different concentrations of essential oils on the mycelial growth of B. cinerea are shown in Fig. 1. All essential oils were found to inhibit the growth of B. cinerea in a dose-dependent manner. Volatile inhibitory effect of essential oils on mycelial growth was greater than contact inhibitory effect (Fig. 1). In the contact phase of essential oils, relatively higher concentrations were required to inhibit mycelial growth as shown in Fig. 1.
Among all the essential oils tested, volatile and contact phases of origanum essential oil caused the greatest inhibition of mycelium growth of B. cinerea at low concentrations (0.2 μg/ml air and 12.8 μg/ ml respectively). Both volatile and contact phases of essential oils of origanum were found to be fungicidal at 0.2 μg/ml air and 12.8 μg/ml respectively. Volatile and contact phases of essential oils of lavender and rosemary were found to be fungicidal at 1.6 μg/ml air and 25.6 μg/ ml concentrations respectively.
Efficient concentration (EC50) values of each essential oil (volatile and contact phases) were also estimated by using Probit analyses. The lowest EC50 values of volatile and contact phases of oils were recorded for origanum essential oil (0.044 and 2.41 μg/ml) was followed by lavender (0.25 and 9.26 μg/ml), and rosemary (0.44 and 10.37 μg/ml) respectively.