Between 1980 and 1986 two serious diseases of Cupressus sempervirens were found in Israel: Seiridium cardinale and Diplodia pinea. Visual symptoms of both pathogens are similar and are eharaeterised by eanker formation aeeompanied by strong resin secretion from lesions. Histologieal examinations in the eentre of the eanker revea1 similar reaetions of C. sempervirens to Seiridium and Diplodia inoculation. Numerous resin duets are formed in the bark, necrophyllaetie periderm formation oceurs several months after inoculation, disorganisation of the xylem is eonspieuous, produetion of abnormal lignified parenehyma eells instead of traeheids oceur at the injured site, and eurved traeheids and transverse walls are formed. Tannin aeeumulation oceurs in the bark and xylem. Similar reaetions of C. sempervirens to wounding and similar effects of Matsucoccus josephi on Pinus halepensis are diseussed.