Maple Bladder Gall: No Cure Once Formed, But Tree Is Fine

Red blotches and drying under gall-covered maple leaves are part of the gall lifecycle. Once galls form, the mite inside is protected—sprays won’t reach it.

Key Facts

• Galls don’t seriously affect tree health.
• Some leaves drop early, but enough remain for photosynthesis.
• Treatment window: only before bud swell (mid-April) targeting adults.

Management

Carbaryl (Sevin) labeled for mites, but rarely needed. Focus on tree vigor: water, mulch, fertilize if deficient. The tree will outgrow the cosmetic issue.

Reference

OSU Extension factsheet: ohioline.osu.edu