Spindle Galls on Flowering Cherry: Eriophyid Mite Damage

Diagnosis

Growths on leaf undersides = spindle galls caused by eriophyid mites (microscopic, 8-legged, not insects). Cosmetic only—no significant health impact on 30+ year old tree.

Life Cycle & Management

• Mites overwinter in bud scales/bark crevices.
• Spring: migrate to emerging leaves, feed, induce gall formation.
• Summer: multiple generations inside galls.
• Fall: return to overwintering sites.

Recommended Actions

1. Sanitation: Rake and destroy all fallen leaves (removes overwintering mites).
2. Vigor Maintenance: Water during drought; fertilize based on soil test.
3. No Spray Needed: Galls don't warrant treatment on mature trees. Dormant oil may reduce spring populations but rarely justified.

Key Point

Do not strip leaves—this harms the tree far more than the galls. The tree will leaf out normally next spring.