European house borer

General information

European house borer (Hylotrupes bajulus) is a destructive pest of seasoned coniferous timber including pine, fir and spruce. Damage is caused by the larvae of the beetle. If allowed to become established it can cause major structural damage to buildings. Infestations are most commonly found in roofing timber.

Emerging adults frequently lay eggs on the same piece of timber. This can continue until no sound wood remains. Wood can be weakened until structures collapse. Larvae of the European house borer are hard to locate and infestations are often only noticed once adults begin to emerge.

The current distribution of European house borer includes Europe, Middle East (Turkey), South America, North and South Africa, China and Asia Minor. It was first detected in Perth, Western Australia, in 2004 and was the subject of an unsuccessful eradication program from 2006 to 2010.

European house borer is now considered endemic in Western Australia, but restrictions remain in place to stop the spread of this pest to other Australian states.

In Queensland, European house borer is prohibited matter under the Biosecurity Act 2014. This means that it is an offence to deal with the pest and its presence should be reported to Biosecurity Queensland immediately.

The Biosecurity Regulation 2016 also requires a biosecurity certificate for the introduction of timber in service from jurisdictions (such as Western Australia) where European house borer has been found.


Species name

Hylotrupes bajulus Linnaeus

What the borer looks like

Adult beetles are robust and a dark grey-brown to black colour and look slightly flattened. Beetles have two raised shiny lumps on their back, just behind their heads. Adults are about 8-25 mm long with antennae about half that length (see Figure 1).

Larvae are rarely seen, as they are hidden in galleries in the wood. They are creamy white in colour with a rippled body and enlarged head. Larvae can grow up to 4 cm in length.

What to look for
  • Frass , a mixture of wood dust and droppings, can sometimes be found on the floor below infested timber where adult beetles have emerged from holes
  • Oval shaped holes in timber, typically 5-10 mm in length, running with the grain on the wood surface
  • Adult beetles, larvae (inside timber) and eggs (laid in cracks and crevices)
  • A soft scraping sound made by the larvae as they feed. This is most likely heard at night, when it is quiet, and can be audible from some distance.
Life cycle

Adult European house borer beetles lay eggs in irregularities such as cracks in pine wood. Dead timber on live trees, untreated structural timber and trash can be infested. Damage to timber is caused by the larvae which can take 2-12 years to develop. European house borer is known to infest architraves, door frames, roof frames and pine furniture. It only infests seasoned, untreated timber.

  • Exotic Pine (Pinus spp)
  • Douglas Fir (Pseudotsugata spp)