PestDecoderDecode a clue

Evidence guide

Frass and pellets

Pellets, sawdust-like debris and mixed wood shavings can separate termites, carpenter ants and wood-boring beetles.

Record the clue before interpreting it

Photograph the debris pile and the point above it. Compare pellet shape, uniformity, grain size and the opening it fell from.

A useful record includes scale, shape, texture, placement and whether the material returns after a clean baseline is established. Avoid changing the scene merely to make identification easier.

What to note

  • Uniform pellets versus mixed shavings
  • Six-sided or irregular pieces
  • Hole or crack directly above
  • Fresh reappearance after a clean baseline
Handling boundary

Do not probe load-bearing wood or treat structural damage as cosmetic. A qualified inspection is appropriate when activity is fresh or widespread.

Read the full safety guide

Common candidates

These candidates are not ranked until location, scale, pattern, context and timing are added. Open a profile to see confirming and contradicting evidence.

high concern

Drywood termite

Kalotermitidae

Uniform hard pellets in small piles directly below tiny wood openings, often recurring after cleanup.

Frass and pelletsWings and swarmersHoles and openings
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high concern

Subterranean termite

Rhinotermitidae

Mud shelter tubes, soft or hollow wood and equal-length swarmer wings near soil-connected routes.

Wings and swarmersHoles and openingsDamage and gnawing
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medium concern

Carpenter ant

Camponotus spp.

Coarse mixed wood shavings below a slit or crack, often with large ants and moisture-damaged wood nearby.

Frass and pelletsWings and swarmersHoles and openings
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medium concern

Powderpost beetle

Lyctinae and related groups

Tiny round holes with flour-like powder accumulating below unfinished or stored wood.

Frass and pelletsHoles and openingsLarvae and grubs
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high concern

Old house borer

Hylotrupes bajulus

Larger oval exit holes, coarse packed frass and feeding sounds in softwood framing.

Frass and pelletsHoles and openingsLarvae and grubs
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Comparisons that resolve common confusion

Side-by-side decision

Termite frass vs. carpenter-ant debris

Drywood termite pellets are uniform and hard; carpenter-ant debris is mixed and fibrous, often with insect fragments.

Wood pestWood pest

Open comparison

Side-by-side decision

Drywood vs. subterranean termite signs

Drywood termites push pellets from wood; subterranean termites preserve humidity with soil-connected shelter tubes.

Wood pestWood pest

Open comparison

Side-by-side decision

Powderpost beetle vs. old house borer

Exit-hole diameter and frass texture are decisive: powderpost signs are tiny and flour-like; old-house-borer signs are larger and coarser.

Wood pestWood pest

Open comparison

Side-by-side decision

Termite pellets vs. powderpost beetle dust

Termite frass remains distinct pellets; powderpost frass behaves like fine flour around tiny round exits.

Wood pestWood pest

Open comparison

Source basis