Leaf Galls on Oak Trees: Cosmetic Issue Requiring No Treatment

What They Are

Pea-sized bumps on leaf undersides are galls formed when insects lay eggs; the leaf tissue grows around them. Larvae feed inside, protected.

Galls cause minor leaf distortion and early drop at worst. They do not threaten tree health. Populations fluctuate wildly year to year.

No control needed. Enjoy the ecological curiosity.

Trees: White Spots on Oak Leaves: Likely Powdery Mildew; Oak Leaf Blister: Cosmetic Fungal Disease; Oak Leaf Fungus at 5000 ft: Cosmetic Leaf Spot Management; Water Oak Top Defoliation: Caterpillars Gone, Systemic for Next Year; Sooty Mold and Honeydew on Oak in South Africa; Red Bell-Shaped Bumps on Oak Leaves: Gall Wasps, Not a Threat; Managing Leaf-Feeding Insects and Fungal Spots on Young Cherry Tree; Cherry Leaf Spot: Fungal Disease on Flowering Cherry; Oak Early Leaf Drop: Drought Response, Not Death; Why Oak Trees Drop Twig Clumps in Spring

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