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Maple Bladder Galls: Cosmetic Mite Damage

What They Are

The red, wart-like bumps on red maple leaves are bladder galls caused by the eriophyid mite Vasates quadripedes. They form in spring, turn red then black, and may distort leaves.

No Treatment Needed

Galls do not harm tree health.
Insecticides are ineffective once galls form.
If severe, apply a miticide in early spring before bud break (consult local extension).

Accept the cosmetic blemish; the tree will be fine.

Trees: Maple Leaf Galls: Harmless Insect Structures, No Human Risk; Red Maple Borer Infestation: Sap Flow and Bud Failure; Red Balls on Maple Leaves: Eriophyid Mite Galls, Not Disease; Maple Spindle Galls: Cosmetic Only, No Treatment Needed; Transplanting a 10-Year-Old Dwarf Red Maple: Timing, Technique & Pro Help; How to Transplant a 10-Foot Red Maple Successfully; Red Maple Leaf Tip Burn: Nutrient Deficiency or Herbicide?; Best Red Maple Varieties for Long-Lasting Fall Color in the South; Maple Leaf Galls: Harmless, No Treatment Needed; Red Maple Leaf Failure: June Diagnosis and Recovery Hopes

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