The most common host of Phytophthora bleeding canker is European beech (Fagus sylvatica). Additional hosts in the region include: maple (Acer), American beech (F. grandifolia), birch (Betula), magnolia (Magnolia), dogwood (Cornus), oak (Quercus), horsechestnut (Aesculus hippocastanum) and walnut (Juglans).
Phytophthora bleeding canker kills the bark and outer sapwood tissues of trees and shrubs. The most prominent symptom of the disease is dark-colored sap oozing from bark cankers. The fluid is typically reddish-brown and it stains the surrounding bark as it flows downward. Infected bark is often water soaked and stained while the inner sapwood can exhibit a range of abnormal colors (brown, bluish-green, orange and pink) depending on the particular species of Phytophthora present. The cankers typically have a well-defined margin that is clearly associated with the bleeding of sap observed from the trunk or scaffold branch. Phytophthora species do not decay wood; they consume sugars in the cambium and outer sapwood. However, the resulting death of the bark and outer sapwood can provide an infection site for wood-rotting fungi to invade at a later time. Research has shown that once Phytophthora invades the outer sapwood, the pathogen can be drawn upwards in the vascular tissue to create cankers higher on the trunk or on main scaffold branches....
