Woodworm

Woodworm Specialists

There are many types of insects that use wood as a habitat. Some insects are restricted to the forest, others can live in timber that has been felled and incorporated into the home. The most commonly known wood boring insect is known as Woodworm, and pre-purchase reports frequently call for woodworm surveys to be conducted and woodworm treatment carried out if required.

Woodworm refers to the larvae of the wood boring beetle Anobium Punctatum, commonly known as Common Furniture Beetle. The larvae lives in the wood for several years, consuming the wood before pupating; the adult woodworm beetle then emerges from the wood, leaving the tell tale signs of frass trails and emergence holes. Woodworm attacks softwoods and the sapwood for European hardwood; however woodworm require wood to be above a certain moisture content to survive.

Common furniture beetle is the most common wood boring insect in the UK. Many older properties will show some evidence (1-2mm exit holes) of woodworm activity in floor boards, joists, rafters etc. although whether this is a current active attack should be determined before any chemical treatment is performed.

All Biocraft South West surveyors are CSRT and CSSW certified, possessing a wealth of expertise in industry standards.

Life Cycle

Adult beetles lay eggs on suitable timber. The eggs turn into larvae which spend 3-5 years eating/burrowing their way through the timber which they inhabit, deriving nutrition and water from the wood. When ready they pupate, chew their way to the surface and emerge from the wood leaving the signature emergence/exit holes.

The emergence period is generally between March/April and September, at which time insects can sometimes be seen on the surface of the wood or flying through the air in a roof space. When the insects emerge they leave a trail or pile of finely chewed wood (frass) which looks like fine saw dust. The presence of this frass is an indicator of current ongoing activity.

Identifying Types Of Woodworm

Evidence of woodworm and Deathwatch beetle is often found in older properties during building surveys. Below is a description of the species which are most commonly referred to in building survey reports. The correct identification of the type of insect that has attacked the timber and whether it is active is a prerequisite of proper treatment. In many cases, there may be no justification for chemical woodworm treatment.

Specialist timber surveys should be carried out by a qualified timber specialist with a minimum of a CSRT (Certificated Surveyor in Remedial Treatments) qualification as required by the Property Care Association (PCA). All Biocraft South West surveyors have achieved the CSRT & CSSW qualification to carry out timber surveys.

Characteristic Features Of Wood Boring Insects

Insect: Anobium Punctatum

Common Name: Common furniture beetle
Type of Timber: Sapwood of soft and hard woods; old plywood (both modern plywood and tropical hardwoods tend to be immune)
Damage: Severe tunnelling with a slight tendency to run along the grain.
Frass (bore dust): Feels gritty; lemon shaped pellets. Uniform, coloured frass, which can be easily knocked out of the wood.
Tunnels: Round, often runs along the grain.
Emergence holes: Round, 1-2mm.

Insect: Hylotrupes Bajulus

Common Name: House Longhorn
Type of Timber: Sapwood of softwoods.
Damage: Severe tunnelling, which is often coalescing; often totally destroys the sapwood. The tunnels are full of frass. Often leaves a sound, thin veneer of wood; the surface often appears corrugated where severe damage is present. Fine ridges usually visible on the surface of tunnels.
Frass (bore dust): Sausage shaped pellets which are visible to the naked eye; Frass is loose and easily shaken from the timber.
Tunnels: Large, oval tunnels; often coalesce.
Emergence holes: Oval, 6-10mm.

Insect: Pentarthrum Huttoni

Common Name: Wood Boring Weevils
Type of Timber: Very decayed hardwoods and softwoods.
Damage: Tunnels run along the grain and frequently break the surface.
Frass (bore dust): Bears a close resemblance to the Common Furniture Beetle.
Tunnels: Round, frequently breaking the surface.
Emergence holes: Round and ragged, 1mm.

Insect: Platypodidae

Common name: Pinhole borer
Type of Timber: Hardwoods and softwoods
Damage: damage occurs in the forest: the insects attack standing trees and freshly felled logs, tunnelling into the wood for long distances across the grain.
Frass (bore dust): None.
Tunnels: The surfaces of tunnels are coloured black/blue.
Emergence Holes: Vary in size depending on the species of beetle, however, many are between 1-2mm.

Insect: Lyctus Brunneus

Common Name: Powder Post Beetle
Type of Timber: Sapwood of wide-pored hardwoods, e.g. oak, with a high starch content (commonly greater than 3%). Timbers over 10 years old are naturally immune.
Damage: Severe tunnelling within the sapwood, commonly running along the grain. sapwood is often entirely disintegrated with only a thin surface of timber left, with excessive amounts of frass present.
Frass (bore dust): Very smooth in texture, almost flour-like, easily knocked out of the wood.
Tunnels: Round, frequently join with other tunnels and tend to run along the grain.
Emergence holes: Round, 1-2mm.

Insect: Xestobium Rufovillosum

Common Name: Death Watch Beetle
Type of Timber: Hardwood with an element of decay present, e.g. oak or elm. Softwoods can be attacked if excessive amounts of decay are present and in close proximity to infested hardwoods.
Damage: Extensive tunnelling; damage may be mostly internal and bears a similar resemblance to the large Common Furniture Beetle.
Frass (bore dust): Feels very gritty; large, bun-shaped pellets of uniform colour which are visible to the naked eye.
Tunnels: Round, with plenty of frass.
Emergence holes: Round, 3mm.

Insect: Ernobius Mollis

Common name: Waney Edge Borer
Type of Timber: Partly or fully seasoned softwoods with bark present
Damage: Confined to the bark, with very superficial tunnelling on the outer sapwood. Emergence holes are rarely further than 15mm from the barked area.
Frass (bore dust): Bore dust feels gritty and contains small, bun-shaped, light and dark coloured pellets.
Tunnels: Superficial tunnelling in the outer sapwood.
Emergence Holes: Round, 2mm in diameter.

Insect: Cerambycidae

Common name: Forest Longhorn
Type of Timber: Softwoods and hardwoods; standing trees, freshly felled and partly dried barked timbers.
Damage: Varies in extent and size.
Frass (bore dust): None, but tunnels may be plugged with coarse fibres.
Tunnels: Very discreet, tunnels do not merge and they tend to run across the grain.
Emergence Holes: 10mm.

Does the Infestation Require Treatment?

Not all species of woodworm require treatment, however, even if a woodworm infestation is identified, it may not be necessary to treat it if the infestation has already died out. It is therefore important to be able to ascertain whether or not woodworm infestation is still active before you consider treatment. In some cases of severe infestation, it may be very obvious that the woodworm is still active, however, in other cases, further investigation may be required in order to determine whether or not the woodworm is still active. These investigations could include:

The presence of fresh bore dust (frass)

The presence of fresh bore dust adjacent to, or beneath, emergence holes can be a strong indication of active woodworm infestation.

The presence of live larvae in timber

The most reliable indication of an active infestation is the presence of live larvae, which may be found in timber that has been removed.

The presence of adult beetles

During the emergence period (generally spring/summer), it may be possible to identify live adult beetles. This is a positive sign of an active infestation.

The presence of new emergence holes

This can be monitored by the “paper test”, which involves lining paper being applied over the surface of timber in areas where active infestation is suspected. The paper can then be monitored periodically over several years: if an adult beetle emerges from the underlying timber, it will also cause a hole in the paper, indicating that the infestation is active.

Specialists in structural waterproofing, our CSSW surveyors can recommend individually tailored systems to suit all types of projects.

Treatment

If active woodworm is detected, then specialist treatment is necessary. The type and extent of the woodworm treatment required will be determined following a specialist timber survey.

The most common form of treatment is the coarse spray application of a preservative, although micro fogging woodworm treatment is available for inaccessible areas. Treatments should only be carried out by a trained operative in strict accordance with the PCA Code of Practice for Remedial Timber Treatment.

Biocraft South West use specially formulated preservatives that allow for the successful eradication of woodworm. To arrange a survey of your property or for further information contact us today. We cover Wiltshire, Somerset, Oxfordshire and Gloucestershire.