Powderpost Beetle
A beetle of new hardwood. It leaves flour-fine dust and tiny holes, and it rarely lasts long.
- Holes are about 1 to 2mm wide
- The dust feels like flour or talc
- It targets starchy hardwood sapwood
What to know about the powderpost beetle
The powderpost beetle attacks the sapwood of hardwoods, such as oak, ash and elm. It needs starch in the wood to grow. For that reason it mostly appears in newly made timber, such as flooring, joinery and furniture.
Infestations often fade by themselves once the starch is used up. Still, you should check the timber, because damage can be heavy while it lasts. Dust that keeps falling means the beetle is active.
| At a glance | |
|---|---|
| Latin name | Lyctus brunneus |
| Adult size | About 3 to 7mm |
| Exit holes | Round, about 1 to 2mm |
| Timber | Starchy hardwood sapwood |
| Active season | Spring and summer |
How to recognise it
You will usually see the damage before you see the beetle. Four clues give it away, because each one leaves a mark.
The adult beetle
It is slim, brown and flat. It looks similar to other small beetles, so rely on the wood and the dust.
The exit holes
Holes are round and about 1 to 2mm wide. They look like furniture beetle holes, but they occur in hardwood.
Bore dust (frass)
The dust is very fine and feels like flour. It trickles from the holes, and it is the best clue.
Damaged sapwood
Only the pale outer wood is eaten. The darker heartwood is usually left alone.
How the beetle develops
This beetle can complete its life cycle faster than other woodworm. A new generation can emerge within a year or so in warm conditions.
Because the starch runs out, old timber is rarely attacked again. New hardwood from the same batch may still carry eggs.
- 1
Egg
The female lays eggs in the open pores of hardwood sapwood. Rough, uncoated surfaces are the easiest targets.
- 2
Larva
The grub feeds on starch and reduces the wood to dust. Because it needs starch, it stays in the pale outer wood.
- 3
Pupa
The larva pupates just under the surface. The wood often looks normal at this stage.
- 4
Adult
The adult emerges through a small round hole in spring or summer. It then mates and lays eggs nearby.
Where it lives and what it does
Knowing its favourite places helps you check the right spots, since each beetle has habits.
Where it is found
Look in new oak flooring, joinery, furniture and imported hardwood. Parquet and panelling are typical.
The damage it does
Sapwood can turn to powder inside a thin shell. Boards can crumble when lifted.
How worried to be
Moderate. Damage can be heavy, but it stops when the starch is gone. A survey shows whether the beetle is active.
How the powderpost beetle is treated
The method depends on the beetle, because each species needs a different approach.
Treatment often uses a surface insecticide on the affected hardwood. Badly damaged boards are best replaced. Ask your supplier to check any new timber before you fit it.
Because infestations tend to fade, a specialist may advise watching the timber for a season. That advice depends on the amount of dust and the age of the wood.
Help in your area
This applies across the UK, but housing differs by city. For local detail, read about woodworm treatment in London and woodworm treatment in Manchester, because older streets hold more old timber.
Powderpost Beetle: your questions
How is powderpost beetle different from the furniture beetle?
It attacks starchy hardwood, and its dust feels like flour. The furniture beetle prefers softwood, and its dust is gritty.
Can it infest old floors?
It rarely attacks old hardwood, because the starch is gone. New flooring is more at risk.
Do I need to replace the boards?
Not always. Heavily damaged boards crumble and should be replaced. Others may be treated and kept.
Is it covered by house insurance?
Policies vary and many exclude gradual damage. Read your policy, and see our cost guide for what to ask.
Helpful next steps
Found signs of the powderpost beetle?
Send your postcode and what you have seen, because the right treatment depends on the species. A local specialist will call to arrange a survey.