From spring 2010 onward, a disease of increasing virulence, was observed in numerous apple (Malus domestica Borkh.) or chardslocated in several Italian alpine valleys. The incidence and severity of the disease in creased during last years and it is becoming a serious economic threat for the area, strongly devoted to apple cultivation. Symptoms of the disease include: alteration of the bark colour that turns to red rusty, occurrence of blisters and flaking off of the epidermis. Underneath, necrosis appear in the external and woody tissues, starting from the grafting point up to the first branch. The extension of necrosis varies from a few centimetres to the whole length of the trunk, but it remains superficial and localized to the outer secondary xylem layer. Symptoms on flower, leaf or fruit are not recorded, although the disease is frequently related to an overall decline of the plant. The reported symptomatology is ascribable tot he “apple blister bark” syndrome.