Journal of Tekirdag Agricultural Faculty, cilt.17, sa.2, ss.264-275, 2020 (ESCI)
Fusarium oxysporum and Pestalotiopsis funerea are the most common fungal disease agents of conifer seedlings causing root rot and shoot or tip blight diseases. In this study, chemical compositions and antifungal activities of essential oils of fennel (Foeniculum vulgare Mill.) and laurel (Laurus nobilis L.) were determined against root rot and wilt disease agents F. oxysporum and P. funerea in vitro conditions. Chemical compositions of essential oils were determined by using GC-MS analysis. Antifungal volatile phase effects of essential oils were determined on inhibition of mycelial growth in vitro conditions by using different concentrations. The effect of most effective concentrations of essential oils on the morphology of fungal hypha was also determined by using light microscope. GC-MS analysis of essential oils of laurel and fennel plants revealed that eucalyptol (52.88%) and α-terpinyl acetate (11.77%) were major components of laurel; trans-anethole (81.55%) and limonene (5.88%) were major components of fennel essential oils. Volatile phase effects of fennel and laurel essential oils were found to completely inhibit mycelial growth of F. oxysporum at 30.0 and 50.0 µl petri-1 concentrations, respectively. Complete growth inhibition of P. funerea by essential oil of fennel and laurel were observed at relatively lower concentrations (20.0 and 25.0 µl petri-1 concentrations, respectively). Light microscopic observations on hyphae, exposed to volatile phase of the most efficient concentrations of essential oil, revealed considerable structural deformations such as cytoplasmic coagulation, vacuolations and protoplast leakage. In conclusion, our results suggest that essential oils have the potential for use in control of fungal diseases of conifer plants.