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Leaf Galls on Unknown Ohio Tree: Harmless Insect Nurseries

What They Are

Green lumps on leaf undersides = leaf galls. Tiny wasp/midge lays egg; chemical expands leaf cells into protective chamber. Larva feeds inside; emerges as adult.

Impact

Cosmetic only.
No health threat.
May cause early leaf drop if extreme.
Populations cycle yearly—next year may have none.

Action: None

No sprays, no removal needed. Natural enemies (parasitic wasps, birds) control populations.

Galls are a sign of a healthy, biodiverse yard. Your tree is hosting the next generation of tiny wasps.

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