Red Maple Borer Holes: Insecticide Treatment and Monitoring

One of two paired red maples has dark trunk holes (more appearing). Other tree fine. Nearby dogwood had borers (treated). Spread possible?

Borer Specificity

Most borers are host-specific. Dogwood borers ≠ maple borers. Some attack multiple hardwoods.

Remove loose bark around wounds
Spray Merit (imidacloprid) or Onyx (bifenthrin) on wounds and into holes
No wound dressing – slows healing
Monitor: re-spray if fresh frass (boring dust) appears after 2 days
Wood-boring species harder to control (insecticide penetration limited)

Trees: Red Maple Leaf Galls: Harmless Insect-Induced Growths; Cracked Bark and Lichens on Young Red Maples; Red Maple Leaf Tip Burn: Nutrient Deficiency or Herbicide?; Japanese Maple Bark Peeling: Often Normal Exfoliation; Maple Bladder Galls: Cosmetic Mite Damage; Choosing Seedless Red Maples for Iowa Landscapes; Leaf Skeletonizing on Bloodgood Japanese Maple: Trumpet Skeletonizer or Minor Damage?; Red Maple Seasonal Color Shift: Sugar Dynamics; Japanese Red Maple Main Trunk Dead, Basal Shoots Alive: Graft Failure?; Seedless Red Maples: Why Your Tree Lacks Helicopters

Garden Articles

Plants