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Woodworm beetles affecting our homes

In the UK, it might surprise you to learn there is a large number of insects that bore into timber either living or dead. However, very few have adapted to infesting timber in our homes and even fewer have learned to thrive under such conditions.

Here we look at some of the more common wood destroying insects (or woodworm beetles) that may be encountered in our homes. 

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Common furniture beetle (Anobium punctatum)

This is the most abundant of the wood destroying insects found in buildings in the UK. The beetle is significant because of its abundance and given the right conditions it can infest a wide variety of timber products, including structural building timbers, and furniture. If left unchecked, in the right conditions, infestations can lead to severe structural weakening and eventually total collapse.

Adult beetles are typically 2.5-5mm long and are reddish to blackish-brown. The upper parts of the body are covered with fine, short yellow hairs. The rows of small pits or punctures on the wing cases are well defined.

Adult beetles emerge from timber in the spring and summer. Females lay eggs, typically into cracks and crevices in the timber. The larvae slowly burrow under the surface of the timber for two to four years. It is this phase that is most  destructive to the timber.

Common Furniture Woodworm beetle in timber - PCA

Mistaken identity?

The common furniture beetle could be confused with the 'usual suspects' below:

Bark borer beetle (Ernobius mollis)

Bark Borer Beetle  - Mistaken Woodworm Beetle - PCA

Sometimes building timbers, particularly rafters, are used with the bark adhering to them. If holes are found in the bark it may lead householders to think that Common Furniture Beetle is present.

The beetle responsible is the Bark borer beetle ('Ernobius mollis'). The attack is normally confined to the bark and there should be no risk to other parts of the wood from attack.

 

Powderpost beetles (Lyctus and bostrichidae - false powderpost beetle)

Powderpost beetle  - Mistaken Woodworm Beetle - PCA

Lyctus beetles are found in unseasoned or recently dried hardwood timbers, principally oak. Like common furniture beetles, the exit holes are about 1.5m but are usually filled with a fine flour-like bore dust (frass) – this differs from common furniture beetles where the frass is coarser, lemon-shaped and gritty.

 

Wood Boring Weevil - PCA

Wood Boring Weevil

The Wood Boring Weevil is arguably the second most common wood boring beetle encountered in the built environment in the UK. Adults are 2.5-5mm long, reddish-brown to blackish, with a snout (rostrum) and long flattish body. Life cycle is short at around 12 months and, unusually, adult beetle also lives for around 12 months. Adults therefore feed and leave characteristic striations (channels) on the timber surface.

Wood boring weevils are restricted in their activities to damp and, at least, partially decayed timber. They are often found behind skirting boards and decaying wall plates where fungal decay is present. Thus, they are normally brought under control by measures taken to deal 
with wet rot. 

Deathwatch beetle 

Its preference for certain partially decayed hardwoods, principally oak, means the Deathwatch beetle is most commonly found in historic buildings such as churches. The best indicator of an active infestation by deathwatch beetle is the presence of adult beetles, typically found on surrounding floors. Organising a survey during the flight season, typically between April and June, is advisable. 

Timber damage can be easily distinguished from that of other wood-boring insects by the presence of small bun-shaped pellets in the frass produced by the larvae and noticeably larger (3mm) flight holes. The beetle is 5-8mm long, and is dark chocolate brown with patches of short yellowish hairs, which give the insect a variegated appearance. In old specimens these hairs may have been rubbed off, in which case the mottled appearance is less obvious. 

Treating an infestation by deathwatch beetles can be particularly troublesome. Treatment with an insecticide by brush or spray during the emergence period of the beetle is useful in destroying eggs and young larvae before they enter the wood, but it is doubtful whether such treatment will kill older larvae working below the surface at any considerable depth.

Deathwatch Beetle - Woodworm Beetles - PCA

Signs of Woodworm

‘Tell-tale’ signs of a woodworm issues - Learn how to identify if you have a woodworm issue.

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How to treat woodworm

Guidance for homeowners looking to treat a woodworm issue. Key Considerations & where you can find help.

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