Sunset Maple Bare Branches: Normal Canopy Habit or Borer Swelling

4-yr sunset maple has leafless gaps on branches (base to tip) and slight trunk swelling at 1.5–2 ft. Owner suspects borer.

Assessment

Inner canopy bare: Normal—leaves concentrate at outer canopy.
Trunk swelling: Likely borer entry. Spray trunk with Merit (imidacloprid)—systemic, kills borers inside.

Merit at nursery stores. Borers attack stressed trees—fertilizer + water reduce appeal.

Plant Diseases: Japanese Maple Honeydew and Sooty Mold: Aphid or Scale Infestation; Maple Cottony Scale Infestation: Large Tree Management Strategy; Sunset Maple Fails to Leaf Out: Cold Injury or Planting Depth?; Maple Leaf Galls: Harmless Insect Structures, No Human Risk; Maple Leaf Scorch from Excess Rain: No Spray Needed This Late; Phyllosticta Leaf Spot on Red Sunset Maple: Spring Fungicide and Fertilizer; Troubleshooting a Struggling Sunset Maple: Water, Nutrients, and Herbicide Risks; Red Maple Borer Infestation: Sap Flow and Bud Failure; Black Spot Fungus on Mature Maple: Why Fall Cleanup Beats Spring Spraying; Maple Borer Infestation in Old Wound: Treatment and Risk

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