Red Bumps on Maple Leaves? Harmless Gall Wasps — No Treatment Needed

Alien-Like Growths on Maple Leaf Veins Explained

Bright red, swollen, curled veins on your Ohio red maple look parasitic — but they're galls caused by tiny gall wasps. The wasp lays eggs, secretes a chemical, and the leaf forms a protective chamber around each larva.

Life Cycle & Impact

• Galls form in days; larvae feed inside all summer.
• Late summer: galls dry, split, larvae drop to soil.
• Zero health impact — only cosmetic. Possible early leaf drop.
• Mild winters = more galls next year, but trees refoliate fine.

Why Spraying Fails

Timing would need to match egg-laying exactly — nearly impossible. Insecticides also kill beneficial predators that naturally suppress gall wasps.

Best Approach: Ignore Them

Your maple is healthy. The "alien" galls are just nature's weird architecture. Rake leaves in fall to reduce overwintering, but don't stress — the tree will be fine.