The composition and antifungal bioassay of the essential oils of differentBetula species growing in Turkey

Five Betula species, B. pendula, B. browicziana, B. medwediewii, B. litwino wii, and B. recurvata, were collected from different parts of Turkey. The l eaves of these species were hydrodistilled to yield the consequent essentia l oils. The essential oil compositions were investigated by GC/MS. 14-Hydro xy-beta -caryophyllene was the main constituent in the oil of B. pendula 14 -Hydroxy-4, 5-dihydro-beta -caryophyllene, a new compound, was identified a s the main constituent in the oils of B. browicziana, B. litwinowii, and B. recurvata. In the oil of B. medwediewii methyl salicylate was the main com pound. Various phytopathogenic fungi were studied by the agar tube dilution technique to test the antifungal activities of the essential oils at 400 m ug/ml concentration. The essential oils showed strong antifungal activity a gainst Cephalosporium aphidicola, Drechslera sorokinianse, Fusarium solani, and Rhizoctonia cerealis.