Red Maple Borer Infestation: Sap Flow and Bud Failure

25-Foot Red Maple in Colorado with Brown Sap and Stalled Buds

Four-year-old red maple shows 1/16″ buds that stopped swelling, brown sap at branch junctions, and browning branch tips. Classic borer attack (likely flatheaded borer).

Immediate Action

Spray trunk and damaged areas with Merit (imidacloprid) or Permethrin labeled for borers. Systemic uptake kills larvae inside. Apply now before further dieback.

Supportive Care

• Deep water weekly during drought.
• Mulch 3 inches to reduce stress.
• Avoid wounding trunk.

Early treatment can save the tree; advanced infestation may require removal.