Plant Problem Diagnosis Key / Diseases
Bleeding canker
Phytophthora spp.
A water mold in wet soil that kills the inner bark and outer wood of the lower trunk. It is most common on European beech, and also hits maple, horse chestnut, birch, dogwood and oak. Large cankers can girdle and kill the tree.
Signs
- Dark reddish-brown to black sap oozing from the lower trunk and staining the bark below.
- Under the bleeding spot, the inner bark is discolored and dead, with a sharp edge against live tissue.
- Thinning crown, small leaves and dieback as the canker grows.
What favors it
Wet, poorly drained or compacted soil, flooding, soil splashed onto the trunk, and wounds near the base.
Prevention
- Plant susceptible trees in well-drained soil and keep sprinklers off the trunk.
- Mulch the root zone to stop soil splashing onto the trunk.
- Avoid wounding the lower trunk and roots.
Crops it shows up on
Shade & ornamental trees; Apple, pear & stone fruit; Roses & ornamentals.
Often confused with
Sources
- Phytophthora Bleeding CankerUMass Amherst Extension
- Phytophthora Bleeding CankerPurdue Landscape Report
Treatment by crop
Cultural, biological and chemical options in the order to use them, and notes written for each crop.
Identification is free. Treatment is on the Home and Pro plans.
Questions in the key that lead here
- Look the plant over, leaf undersides included. Are insects, mites, slugs, eggs, webbing or droppings on it?
No, only damage or discoloration - Where is the problem?
A tree or shrub - Which part of the tree or shrub shows the problem?
The trunk or bark - What is in or on the bark?
Sunken, discolored or dead patches of bark - Where is the dead bark, and what is with it?
Dark reddish-brown or black sap bleeding from the lower trunk
Not a match? Start the key or describe what you see.
More from university Extension: search Extension pages on bleeding canker, or find a plant diagnostic lab through your state's Extension.
Other diseases
- Anthracnose
- Apple scab
- Bacterial leaf scorch
- Bacterial leaf spot
- Bacterial wetwood (slime flux)
- Bacterial wilt of cucurbits
- Black knot
- Black spot of rose
- Boxwood blight
- Canker diseases
- Cedar-apple and related rusts
- Crown gall
- Damping-off
- Downy mildew
- Dutch elm disease
- Early blight and Alternaria leaf spot
- Elm yellows (phloem necrosis)
- Fire blight
- Fusarium wilt
- Gray mold (Botrytis)
- Late blight
- Mosaic viruses
- Needle cast and tip blight
- Oak wilt
- Powdery mildew
- Root and butt rot
- Root rot (Pythium and Phytophthora)
- Rust
- Septoria leaf spot
- Shade tree anthracnose
- Sooty mold
- Tar spot of maple
- Tomato spotted wilt and impatiens necrotic spot viruses
- Verticillium wilt
- White mold (Sclerotinia)
- White pine blister rust