A House Full of Boring Insects, or How not to Have Your House Eaten (Again) Content from the guide to life, the universe and everything

A House Full of Boring Insects, or How not to Have Your House Eaten (Again)

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House being eaten

For the uninitiated, this entry follows a previous guide to not having your house eaten by dry rot. Now it's time to talk about piles. No, not those (painful, aren't they), but those little piles of sawdust you keep noticing when Henry the Hoover has one of his infrequent airings1.

Worrying, aren't they?
Sure about that?

We usually share our homes and lives with a host of insects, like it or not. Most of them are completely harmless, some are mostly harmless. Some, however, are a complete bunch of timber-munching, frass-making boring beetles, and need to be dealt with.


To start with, the one that most people have at least heard of is the Common Furniture Beetle (Anobium Punctatum), or woodworm. These little blighters live in cut and dried timber, where it tends to be the larvae that cause the most damage by gnawing along the grain under the surface2. The adults emerge through the timber to mate (usually between May and September), leaving a 1-2mm hole, and a pile of fresh dust, called frass. The frass will be slightly gritty when rubbed between finger and thumb, and under magnification will be small, lemon shaped pellets. Woodworm are not keen on painted or varnished timber and not overly fond of most hardwoods3. Softwood floors (particularly the underside and the edges of the floor boards) and roof timbers are favourite prey, but they will also attack old furniture, picture frames and, of course, pianos. To do any serious damage, they have to be ignored for a pretty long time, and happily treatment is fairly simple using permethrin-based insecticide. Modern treatments use micro-emulsions which are basically tiny globules of treatment in a water suspension, meaning that treatment is much less hazardous, and with lower odour.

The furniture beetle is widespread across Northern Europe and other nations with temperate climates4, particularly Germany but also Scandinavia, as well as Asia, parts of Africa and New Zealand.

Mistaken for Woodworm

Commonly mistaken for woodworm are several other species such as:

  • Wood Weevil (Euophryum sp.) which live in very wet timber, but are smaller and tend to do more damage along the line of the timber grain. Originally from America, they are now found in temperate climates worldwide.

  • Biscuit Beetle (Stegobium sp.) which are about the same size or a little smaller, but live on discarded crumbs, grain, cat biscuits etc. These tend to be a reddish-brown in colour, and have a smooth pronotum (the bit that covers the top of the head) whereas the Furniture Beetle has a pronounced hump like a monk's cowl. The biscuit beetle is also found in temperate climates worldwide.

  • Bark Boring beetles (many species, depending on the type of tree) which only live beneath the bark of live or recently felled trees. Most commonly noticed when people bring logs into the house for their wood burner - the adults emerge and congregate on window ledges, trying to get back out again.

Watch Out! The Deathwatch Beetle

If you are fortunate enough to live in a nice period house with oak beams (or you are considering buying one), you may be lucky enough to be woken in the dead of night by a clicking sound like the ticking of a large watch. This may belong to the Deathwatch Beetle (Xenobium Rufovillosum), a persistent offender and serial chomper. These little devils make larger holes than woodworm, typically 4mm, with more frass which is dark brown or black, and bun-shaped. Deathwatch have a much longer lifecycle than woodworm, and the deep-seated larvae can be difficult to treat. If left unchecked, they can make a serious mess of a piece of oak, and render it structurally as much use as dried spaghetti.

The Longhorn and the Short of It

Far less common is the House Longhorn Beetle (Hylotrupes Bajulus), a really nasty woodborer imported into the UK by mistake and generally found in some areas of South London and Surrey (hence the other common name, the Camberley Beetle). These insects really do make a mess of softwood timber, often eating the insides and leaving a thin veneer of timber on the outside. Exit holes of the adult beetles are oval and around 10mm across. Treatment of these involves removing any infected timber (and normally burning it) and treating the rest with some seriously heavy-duty jollop5. Not for kids or the faint-hearted.

Also uncommon, but often mistaken for woodworm, is the Powder Post Beetle (Lyctus Brunneus), which is also a forest insect but can survive the cutting and drying process to be incorporated into furniture and flooring. Exit holes are about 2mm across, but the frass tends to be tightly packed and has the consistency of fine flour. They will not infect any other cut timber, and there really is no treatment available. The best advice is to get reparation from whoever sold you the offending article under the Sale of Goods Act (or equivalent), as the goods are not fit for purpose.


The best advice we can give is that you


  • Contact a reputable company6.

  • Get a proper inspection by a qualified surveyor.

  • Get it treated if possible.

  • Get a decent guarantee worth more than the paper it is printed on (most reputable companies offer insurance-backed guarantees7).


  • Leave it and assume it will be fine.

  • Hack away at innocent bits of timber or random beetles with axes, knives or any kind of sharp things.

  • Swear at them (they rarely understand English, or if they do they're not admitting it)
  • Attack it with a flamethrower(!)

  • Panic.

1Technically two different manufacturers, but the Researcher is an equal opportunities vacuum user.2Sapwood is the softer, newer wood between the tree's bark and heartwood.3Hardwoods come from flowering trees particularly deciduous trees and evergreens whereas softwoods come from trees that grow seeds alone, such as conifers, pines and cycads.4Temperate climates are found in the land between the Arctic Circle and Tropic of Cancer in the Northern Hemisphere, and between the Tropic of Capricorn and Antarctic Circle in the Southern Hemisphere. In other words, not the tropics or subpolar regions.5'Jollop' is a word meaning strong medicine or, in this case, chemicals.6In the UK try the website of the Property Care Association and look for a member.7This ensures that if the company goes out of business the insurance company pay for any remedial work.

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