Composition of essential oils from Cupressus lusitanica and a Xylariaceous fungus found on its leaves

► The essential oils of Cupressus lusitanica and its endophytic fungus were studied. ► Some monoterpenes and sesquiterpenes were found in essential oils of both organisms. ► Antifungal activity from plant essential oil was tested against its endophyte. ► The plant volatile compounds may control its endophytic population.