Silver Maple with Bark Loss and Borers: Emergency Intervention

A 15-year-old Indiana silver maple shows 2 feet of missing bark exposing smooth wood, worms under loose bark, 50% leaf loss with brown/wilted foliage, but some green shoots at branch tips. Owner wants to save it.

Diagnosis: Borer Infestation in Stressed Tree

Two likely culprits:

• Maple callus borer (Synanthedon acerni): Clearwing moth larvae boring around wounds. One generation/year.
• Sugar maple borer (Glycobius speciosus): Longhorned beetle larvae tunneling in sapwood. Two-year cycle. Can girdle trunks.

Both attack stressed trees. The bark splitting and loss suggest prior injury (frost crack, mechanical damage) invited borers.

Immediate Treatment Plan

1. Insecticide Application

• Trunk spray with Merit (imidacloprid): Kills adults before egg-laying and larvae in bark. Time to adult flight (varies by species).
• Soil systemic (Bayer Advanced): Alternative for season-long uptake.

2. Fertilize for Vigor

10-10-10 at 1 lb per inch trunk diameter, scattered to drip line, watered in. Borers target stressed trees—improving health is essential.

3. Monitor and Remove Deadwood

Prune confirmed dead limbs (scratch test) in dormant season. Don't remove live tissue with green shoots.

Prognosis

Recovery possible if:

• Cambium (living layer under bark) is intact on majority of circumference
• Borers are controlled
• Tree vigor improves

If >50% circumference is girdled, survival is unlikely. Consult an ISA-certified arborist for structural assessment.