Understanding woodworm to truly fight it
Not all woodworm is the same, and the damage it causes is almost always more advanced than what you can see. By the time a piece of furniture or a beam shows its first holes, the insect that made them has already left: the real damage happened beneath the surface, out of sight, for months or years.
On this page we share what more than fifty years of working with wood have taught us: the biology of the insect, the signs of an active infestation, the three most common species, and an aspect that is often overlooked — the link between woodworm and certain parasites that directly affect human health.
What woodworm is and how it lives
Silent beetles, capable of boring for years unseen
Woodworm belongs to the beetle family and is among the most aggressive and damaging insects for wood. The reason is simple: wood provides everything the insect needs to live and reproduce — vitamins, proteins, water. Neglect, lack of maintenance, damp and darkness all favour its development; so does the warmth of domestic heating, which removes winter dormancy and lets the insect stay active all year round.
The cycle is fast and silent. The female lays her eggs; on hatching, the larvae emerge and immediately start feeding on the wood, boring internal tunnels. This is the destructive phase: while they feed, woodworm larvae are small grubs hidden deep inside the wood. As they approach the surface they undergo a final transformation and, as adults — now with a hard shell protecting their wings — bore their way out, fly off, and die shortly after.
Which leads to a fact worth remembering: every visible hole marks an insect that has already left. The hole is not the start of the problem — it is its final signature.
How to recognise an infestation
Three signs worth watching for
Woodworm works in silence. As it eats away at the wood from the inside it produces no perceptible sound, which is exactly why an infestation can go undetected for a long time. Some species have a life cycle of more than ten years: furniture and beams can look perfectly sound on the surface while everything underneath is gradually being hollowed out.
- Exit holes, left by the emerging adult insects. Size matters: some species leave holes under a millimetre wide, others can exceed a centimetre in diameter, a sign of a more aggressive infestation.
- Wood dust (boredust) that comes out of the holes or collects beneath the piece.
- A faint ticking sound, most noticeable during quiet hours: this is not the sound of the insect feeding, but the adult beetle repeatedly striking its head against the wood — a mating call to which both sexes respond.
If you hear the ticking or find fresh dust, the infestation is active and in its reproductive phase: this is the moment to act, before a new cycle begins.
The three most common species
Knowing the species helps assess severity and urgency
Not all woodworm attacks the same wood, or with the same severity. These are the three most common.
Anobiidae
The family Anobiidae includes the species most common indoors: the common furniture beetle (Anobium punctatum) and Xestobium rufovillosum.
These develop mainly by feeding on hardwoods such as walnut, mahogany and ebony, but will also attack the softer wood of conifers and broadleaf species. The cycle is normally annual, but in warm, humid climates they can complete two or three reproductive cycles in a single year. Only a very dry climate hinders their development — a condition rarely achieved indoors.
Cerambycidae
The family Cerambycidae includes the house longhorn beetle (Hylotrupes bajulus), among the most damaging species for structural timber; Callidium violaceum belongs to the same family.
These favour conifer wood — spruce, silver fir, pine, larch — and softwoods in general. They are among the most insidious species, because the first visible damage only appears after two or three years. The cycle, from egg to exit hole, ranges from 2-3 years up to 10-12 years. The larvae bore tunnels between bark and sapwood; the female lays up to 400 eggs, spread across several batches in locations far apart from one another.
Lyctidae
The most widespread species are Lyctus linearis and Lyctus brunneus, now placed in the family Bostrichidae (subfamily Lyctinae) and traditionally classified as Lyctidae.
These attack broadleaf woods such as oak, ash, chestnut, walnut, black locust and exotic species. The cycle is normally annual, but can reach two or three cycles a year in heated environments, regardless of humidity. They bore tunnels following the grain of the wood. The insect ranges from 2 to 7 mm in size.
Not just wood: woodworm parasites
A health issue, not only a conservation one
There is a less well-known but important reason why a woodworm infestation should not be underestimated: beyond damaging wooden structures, woodworm can host parasites that are harmful to humans. This is why Timpest has invested in research and expanded its range of woodworm treatments. Eliminating the woodworm also eliminates its parasites — and the skin reactions they cause.
The woodworm mite (Pyemotes ventricosus)
An arachnid invisible to the naked eye (0.2 mm), parasitic on furniture woodworm. Contact with humans occurs through fabrics, bedsheets and clothing; only females bite, drawn by the carbon dioxide given off by the body. The bite itself is barely felt, but the resulting lesions — affecting the pelvis, torso, limbs, neck and sometimes the face — require medical attention. Dermatitis cases peak in the warmer months, from late May to late September. There is only one way to get rid of it: eliminate the woodworm that hosts it.
Domestic Scleroderma wasp (Hymenoptera Bethylidae)
A 3-4 mm micro-wasp resembling a small ant, which develops by feeding on woodworm larvae — typically where Anobiidae are present. It infests any type of wood attacked by woodworm, with outbreaks common in stores of dry or decaying firewood. Its sting is noticeable, as it injects a venom that triggers dermatitis: a single individual can cause up to 40 lesions, spread across the pelvis and torso. Here too the peak is in summer (late May to early July) and treatment requires a doctor. And here too the underlying solution is the same: eliminate the woodworm.
The solution starts with the right product
Knowing the enemy is half the job. The other half is treatment: an effective woodworm product that penetrates deep into the wood and acts by contact and ingestion, eliminating the infestation at its root and protecting the piece over time. The Timpest range covers every need — from the classic solvent-based formula to water-based solutions for indoor and outdoor use.
Frequently asked questions
How can you tell if woodworm is still active?
Three signs point to an active infestation: recent exit holes, fresh wood dust beneath the piece, and a faint ticking sound audible during quiet hours. Fresh dust and ticking mean the infestation is active and in its reproductive phase.
Why do the holes appear once the insect has already left?
The destructive phase is the larval one and takes place inside the wood, where larvae bore tunnels for months or years. The hole is made by the adult on its way out: it is the final signature of the cycle, not its beginning.
Which woodworm species attack wood indoors?
The three most common families are Anobiidae, which mainly attack hardwoods; Cerambycidae, which favour conifers and include the house longhorn beetle (Hylotrupes bajulus); and Lyctus, which attack the sapwood of broadleaf species. The cycle ranges from one year to more than ten, depending on the species.
Is woodworm dangerous to health?
Woodworm itself does not attack humans, but it can host parasites that do: the mite Pyemotes ventricosus and the micro-wasp Scleroderma, whose bites cause skin lesions. Eliminating the infestation also eliminates its parasites.
When is curative treatment needed, and when preventive?
Curative treatment is used when an infestation is under way: it acts on wood-boring beetles, with rapid action on the house longhorn beetle (Hylotrupes bajulus). Preventive treatment protects sound wood and also covers subterranean termites (Reticulitermes sp.).
Can already varnished wood be treated?
Not directly. Paint, lacquer and wax form a film that prevents absorption and reduces the product’s effectiveness: they must be removed before application. Treatment requires clean, dry surfaces.
Use biocides safely. Always read the label and product information before use.