Cherry Tree Black Canker: Professional Diagnosis Needed

Your white cherry with curled black leaves and blackened young shoots in Cupertino, CA, likely has black knot (Apiosporina morbosa) or a Phytophthora collar/crown rot. Both cause blackening and dieback.

Key Differences

• Black knot: Distinct black galls on branches, rough texture.
• Phytophthora: Blackening at soil line, oozing, sudden wilt, poor drainage link.

Action

1. Contact UC Cooperative Extension (link in original) for county-specific advice.
2. Photos help: Base of trunk, affected branches, leaf symptoms.
3. Check soil drainage—cherries hate wet feet.

Why Professional Help

Cherry diseases in CA are complex (bacterial canker, brown rot, Phytophthora, black knot). A local farm advisor or arborist can ID the pathogen and prescribe legal, effective treatments for your county.

Don't guess—cherry diseases spread fast and kill quickly.