Holes in wood

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Signs of wood borers

Wood boring beetles can cause significant damage to buildings and wooden products. If timber is untreated and an infestation is undetected for some time, wood boring beetles can seriously weaken it and lead to structural failure.

The beetles live most of their lives inside the timber so you may not realise that you have a problem until the adults emerge from the timber. It is vital that an infestation is detected as soon as possible and the timber is treated to prevent further damage. This page describes the many signs that can show you have an infestation of wood borers.

How can you spot wood borers?

There are multiple signs that can tell if wood borers have infested timber or wooden products. Scroll down or click on the links below to see the details: 

Fresh exit holes in timber

The holes are created by the adult beetles emerging from the timber. They can be found all year round, but mainly form during summer months in temperate climate areas. The round or oval exit holes are 1- 2mm in diameter for the common furniture beetle and powderpost beetle, but 3-7mm for the larger house longhorn beetle. Woodworm exit holes will appear clean and fresh and often have sharp edges.

Bore dust or frass

Bore dust, also known as frass, is caused by emerging adult wood boring beetles. It is composed of faeces and wood fibre. It will usually be visible below the infested timber, but also, as in the photo, on the timber itself when it is at an angle.

Tunnels in wood

Tunnels in wood, also known as galleries are the result of the larvae of wood borer larvae boring through timber. These are usually hard to see as, obviously, they are inside the wood, but can also become visible when timber is sawn or tight-fitting timber in a building is separated. The house longhorn beetle larva at first may stays near the surface of wood and can leave a blister like appearance on the surface. The larva is much larger than the other wood borers so its tunnels are also larger at up to 7.5 mm in diameter.

Have you seen tunnels in wood? Contact us to arrange a professional survey of your property

Weak and damaged floor boards

Floor boards start to bend or give way when pressure is applied. In extreme cases, a foot or chair leg going through the floorboard can indicate a more serious infestation.

Crumbling wood

Crumbling wood is caused by multiple tunnels and rotting wood. It can often first be found around corners or edges of roof joists or floorboards.

Live adult beetles

Adult beetles emerge from timbers in summer to mate and lay more eggs in timber nearby. The common furniture beetle (Anobium punctatum) is about 4mm long and chocolate brown. It only occurs in the cooler southern Australian states and attacks both softwood and hardwood. The powder post beetle (Lyctus brunneus) is about 7 mm long and dark brown. This wood borer only attacks starchy sapwood of some hardwoods.

Have you seen live or dead beetles? Contact us to arrange a survey of your property

Dead beetles

Dead wood borer beetles can be found near the infested timber or around nearby window sills which they are attracted to by light. They can fly so will not just occur below their exit holes.

The discovery of dead beetles can indicate a previous or a current wood borer infestation. Dried out bodies can remain for some time if undisturbed so do not necessarily indicate a current problem.


Common furniture beetle eggs are whitish, 0.35 mm wide and 0.5 mm long. The females lay the eggs in cracks, crevices or joints in timber in groups of 2-4.

The powderpost beetle lays the eggs in exposed ends of vessels of hardwoods, which are larger than softwood species. Eggs are about 1mm long and 0.15mm wide. The beetle may lay several eggs in one vessel The longhorn beetle eggs are greyish white, 1-2mm long and about 0.5mm broad. They are also laid in cracks and crevices.

Wood borer larvae

Wood borer larvae are usually a creamy-white colour and curved in shape. However, these are rarely seen unless infested timber is sawn or broken open as they spend all their time in the wood.

Only the adults exit the wood. The larva of the powder post beetle is 5mm when fully grown, the common furniture beetle larva grows to 7mm long and the longhorn beetle larva reaches 24mm in length. Time spent as a larva inside the wood is dependent on temperature, humidity and food supply.


The larvae of the house longhorn beetle can be heard scraping the wood inside their tunnels at times of the year when they are most active.

How to deal with a wood borer infestation

Our professional surveyors will carry out a thorough inspection to identify the signs of woodworm and assess the type of woodworm involved. They will also determine if the infestation is active, check for associated problems such as wood rot or damp and if any timbers need replacing.

Based on this detailed evaluation they will then recommend appropriate wood borer treatment.

Call Rentokil today on 1300 307 938 or Contact us online to arrange a survey of your property.



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