What Does Woodworm Look Like?

Woodworm is the term used to describe the larvae of several species of wood-boring beetle. These larvae live and feed inside timber for years, causing structural damage before emerging as adult beetles.

The first step to protecting your property from woodworm is knowing what woodworm looks like: both as different types of beetle and their larvae, and the telltale signs of woodworm damage.

If you think you’ve seen the signs of a woodworm outbreak, think you’ve spotted a wood-boring beetle in your property, or had woodworm flagged during a homebuyer’s survey, a professional timber survey from our woodworm specialists can give you a definitive answer.

Knowing how to tell if you have woodworm starts with understanding the physical signs of damage rather than trying to spot the larvae themselves.

Wood-boring larvae often take up to five years to work their way through wood before emerging in their adult form. This means that the damage is often already done by the time homeowners see beetles.

If you spot signs of woodworm, it’s important to contact a specialist to find out if an infestation is still active. Even if the beetles have already emerged, they may have laid more eggs that will continue the cycle.

Correctly identifying the type of wood-boring beetle is essential before treatment begins. Different species target different timber, act in different ways, and require different approaches.

• Adult size: 3-5mm
• Features: Chocolate brown, domed pronotum that hoods the head, fine regular lines on wing cases.
• Larvae: Cream-white, curved, small brown head. Grows from 1mm at hatching to around 4mm before pupating.
• Lifecycle: 3-5 years
• Exit holes: Round, 1-2mm
• Frass: Gritty, cream-coloured and lemon shaped.
• Wood preference: Softwood and hardwood sapwood. Floorboards, roof timbers, furniture, old plywood.
• Common in Scotland? ✅ Most common species in Scotland, responsible for over 80% of woodworm damage.

• Adult size: 3-5mm
• Features: Brown to black. Distinctive rostrum snout with antennae positioned one third along the snout. Unlike most species, both the adult and larva eat wood.
• Larvae: Cream-white, curved. Found in soft, already-decayed timber.
• Lifecycle: 1 year
• Exit holes: Around 1mm, ragged, tends to follow the grain
• Frass: Fine and gritty.
• Wood preference: Damp, decayed timber only. Cannot survive in sound dry wood.
• Common in Scotland? ✅ Common, particularly in coastal areas where persistent damp is present.

• Adult size: 4-7mm
• Features: Mid reddish-brown, flattened and elongated body shape
• Larvae: Cream-white, curved. Found in recently cut hardwood sapwood rather than older timber.
• Lifecycle: 1 year
• Exit holes: Round, 1-2mm
• Frass: Very fine, flour-like. Smooth when rubbed between fingers.
• Wood preference: Sapwood of wide-pored hardwoods. Oak flooring, kitchen units, green oak. Timber is typically under 15 years old.
• Common in Scotland? ✅ Common in new builds and properties renovated with imported hardwood products.

• Adult size: Varies by species
• Features: Often brightly coloured. Long antennae equal to or exceeding body length. Several species found across Scotland.
• Larvae: Cream-white, elongated. Much larger than Common Furniture Beetle larva.
• Lifecycle: 2-6 years
• Exit holes: Large, elliptical
• Frass: Varies by species
• Wood preference: Softwood and hardwood sapwood. Most commonly found under the bark of logs brought indoors rather than structural timber.
• Common in Scotland? ✅ Common, though most frequently associated with logs rather than structural timber.

• Adult size: 5-7mm
• Features: Chocolate brown with patches of yellowish hairs, giving a mottled appearance. Produces a distinctive tapping sound to attract a mate.
• Larvae: Cream-white, robust. Grows to around 11mm.
• Lifecycle: 4-5 years but can be longer. Difficult to treat due to size and density of timbers, as well as long post-treatment emergence period.
• Exit holes: Round, approximately 3mm
• Frass: Bun-shaped, coarse. Readily visible to the naked eye.
• Wood preference: Decayed hardwood, particularly oak. Begins in fungally decayed timber before spreading to adjacent sound wood.
• Common in Scotland? ⚠️ Rarely found in Scotland. Most commonly associated with historic properties in England and Wales with large structural oak timbers.

Woodworm larvae characteristics differ by species, but tend to be cream-white and grub-like with a darker head. It is rare to see a woodworm larva, as they live entirely inside timber and are rarely visible without cutting wood open. If you do spot larvae on a surface in your home, it is likely from a different species entirely, which is another reason why professional identification matters before any treatment is carried out.

If you’ve spotted signs of woodworm in your property, a professional damp and timber survey is the right first step.

A Wise Property Care surveyor will confirm whether the infestation is active, identify the species involved, assess moisture levels and timber condition throughout your property, and provide a clear report with honest recommendations. Woodworm treatment is only ever recommended where it is genuinely required.

Wise Property Care has a number of PCA qualified surveyors operating across Scotland from our network of local branches.