Chemical changes in Ulmus minor xylem tissue after salicylic acid or carvacrol treatments are associated with enhanced resistance to Ophiostoma novo-ulmi

► Elm trees were treated with either salicylic acid (SA) or carvacrol (CA). ► SA-treated trees showed a marked accumulation of sinapyl alcohol. ► CA-treated trees showed a marked change of fatty acid composition. ► Both treatments resulted in enhanced tree resistance to Dutch elm disease.