Large White Grubs in Maple Tree Base: Borers

45-year-old purple maple: Loose bark, rotten underneath, two 3-inch white grubs (pencil-thick) curled at base.

ID: Tree Borers (Beetle Larvae)

• Enter through wounds/bark cracks.
• Larvae tunnel in cambium/wood.
• Maple = thin bark = vulnerable.

Immediate Action

1. Remove grubs: Dig out or kill with wire probe.
2. Spray trunk: Merit (imidacloprid) or Onyx (bifenthrin) — check local garden center.
3. Fertilize: 10-10-10 at 1 lb/inch trunk diameter, water in.
4. Water deeply during drought.

Prevention

• Inspect trunk Sept & May for sawdust/frass.
• Protect bark from mower/trimmer damage.
• Mulch ring (not against trunk).

Borers attack stressed trees. Vigor = best defense.