Phytophthora Bleeding Canker

Phytophthora Bleeding Canker Description:

Phytophthora bleeding canker is a disease caused by multiple species of Phytophthora, which invade the bark and outer sapwood of trees. The pathogen is known to attack shrubs and trees that are already under stress, and maybe fatal to trees–if left untreated.

Hosts:

European beech trees are the most common host of Phytophthora bleeding canker, however, the following trees have also been common hosts:

• Maple
• American beech
• Birch
• Magnolia
• Dogwood
• Oak
• Walnut

Biology & Symptoms:

The most obvious symptom is a dark sap oozing from bark cankers. Phytophthora bleeding canker kills the tree’s surface tissues, turning the inner sapwood dark red to reddish-brown. The bleeding cankers may serve as an entry point for insects or other pathogens. Foliage may decrease or drop prematurely, and branch dieback will usually occur.

Disease Treatment & Management:

Early detection of this disease is vital for treatment. If detected in time, trees that are not severely diseased are often able to recover. There are also fungicide treatments that, if applied properly, may help to protect the tree against bleeding canker. If damage is severe enough, removal may be necessary to prevent the disease from spreading to nearby healthy plants. If you suspect your trees may be suffering from Phytophthora bleeding canker, consult your local arborist to have them evaluated and determine what treatments are right for your property.

*Photo credit: Bruce Moltzan, USDA Forest Service, Bugwood.org