Diplodia bulgarica has been recently identifed on apple trees in Bulgaria and Iran. This fungus was isolated from apple trees in the west of Iran, showing canker, gummosis, dieback and twig blight symptoms. To determine its signifcance as a pathogen on apple, Koch’s postulates were fulflled by stem inoculation of 2-year- old apple trees (cv. Golden Delicious) under greenhouse and feld conditions. Results confrmed D. bulgarica as a highly virulent pathogen on apple under greenhouse and feld conditions. This is the frst record of D. bulgarica as a pathogen of apple, emphasizing the need to study biological and genetic aspects of this new pathogen.
