European House Borer

Hylotrupes bajulus L.

Family: Cerambycidae (Longhorn beetles)

Order: Coleoptera

Other Names:

Old-house borer - refers to their occurrence in old houses that were commonly built with untreated timber, however they are more common in new houses that include untreated softwoods that are infested with eggs.


A destructive pest of seasoned or dead coniferous timber such as pine, spruce and fir (e.g. Oregon). Infected timber may show no outward signs of the infestations until the adult emerges some years later leaving an oval shaped hole aligned with the grain of the timber. Gnawing of the larvae inside the wood can sometimes be heard in quiet conditions. The adult beetles are 8-25 mm long, black or brown with greyish hair on their upper bodies and wing cases. They have shiny black conical bumps that resemble eyes on the thorax. The larvae are cream, up to 40 mm long with a rippled body and enlarged heads with dark brown mouth parts. They live in tunnels inside the wood that are usually tightly packed with frass. A fine powdery mixture of wood dust and droppings (frass) is sometimes seen on the floor below the holes where the adults emerge from the wood. Long blister like swellings are occasionally seen where the tunnels come close to the surface of the wood. Damage and tunnels are not usually apparent until the wood is planed, sawn or split. Characteristic oval shaped holes, 5-10 mm long, in wood where the adults emerge from infested timber can sometimes be found


Adult -
Colour - Black to brown or greyish.
Body - 8-25 mm long, cylindrical to slightly flattened. The female is larger than the male.
Wings - Elytra (wing cases) are all black or have white patches or two pairs of light grey horizontal bands.
Mouthparts -
Antennae - 5-10 mm long.
Legs - 6.
Head - .
Thorax - hairy with two shiny black conical bumps
Abdomen -
Habits -
Caterpillar -
Colour - Cream
Body - up to 40 mm long and cylindrical.
Mouthparts - dark brown to black
Antennae -
Legs -
Head - Enlarged and flattened. There is a row of three small black single-lens eyes on each side of the head.
Body - rippled.
Habits - Soft scraping sounds can often be heard as the larva chews through the wood.
Pupa -
Eggs - Laid in batches of up to 120 eggs.

Key Characters:

Chewing/rasping mouth parts.
A row of three small black single-lens eyes on each side of the head.
Smooth flour like frass.


Life Cycle:

The adult beetle lays its eggs in batches in cracks or joints of dead or untreated seasoned softwood or in dead branches on trees. The larvae emerge from the eggs and live concealed in the timber for 2-12 years. They then pupate then emerge through 6-10 mm wide, oval shaped, exit holes aligned with the grain of the timber.
Emergences usually occur in the spring and summer and adults are active over summer.


Prefer temperate climates.
Seasoned, untreated pine, fir and spruce timber and deadwood.

Origin and History:

Originally from Europe.
It was found in the eastern states of Australia in the 1950s and was eradicated by 1970 after one of the world's largest fumigation programs.
In 2004 it was been found in Western Australia and is the focus of an eradication program.


Worldwide distribution including Asia, Asia minor, Australia, Canada, China, Europe, Mediterranean, Middle East, South Africa, South America and the USA.


It may cause structural damage in buildings that have untreated softwood such as pine fir and spruce. In WA it has damaged radiata pine, southern pine, Douglas fir, hoop pine and bunya pine. It is most common in roof timbers but is also found in architraves, door frames and furniture. It may invade from wood piles and dead trees or branches.


They recycle dead softwoods.


Damages structural integrity of timber and furniture.
Attacks and eventually causing structural collapse in Pine (Pinus species), Spruce and Fir such as Douglas fir (Pseudotsuga species) which is commonly called Oregon.


Declared species in Western Australia. All suspect infestations must be reported to the Department of Agriculture. An eradication program is underway.
There are Restricted Movement Zones for pine in Western Australia. Contact the Department of Agriculture for the latest list.

Management and Control:

Report to local Department of Agriculture.
Don't collect dead softwood for firewood as this may spread the infestation when mature insects emerge and lay eggs on timber and furniture in your house or in adjacent plantations and gardens.
Burn all untreated softwood off-cuts and dead coniferous branches and wood.
Collect and destroy dead pine, spruce and fir branches and deadwood.
Fumigate infested furniture and wood or treat with insecticides.
Use treated wood for furniture and construction.
Cover untreated pine with plastic to prevent adults laying eggs on it.
For small infestations, treat with bifenthrin or permethrin mixed in oil to achieve maximum penetration immediately and repeat in spring each year for at least 6 years or until all activity has ceased.


Very low.

Related Species:

Similar Species:

Furniture beetle (Anobium punctatum) has smaller 1-2 mm exit holes that are round rather than oval. The frass feels gritty when rubbed between the fingers.
Powder post beetle (Lyctus and Minthea species) has smaller 1-2 mm exit holes that are round rather than oval. They attack the sapwood of hardwoods and cannot attack softwoods such as pine.
Queensland pine beetle (Calymmaderus incisus)


CSIRO. The Insects of Australia. Melbourne University Press. (1991)

WADA. (2009) European House Borer Response. Exotic Pest Fact Sheet


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