Guide to woodworm problems

Page 1: What is woodworm?
Page 2: What damage can woodworm cause?
Page 3: What does it cost?

Anna Heywood - Writer

What is woodworm?

Woodworm refers to the larvae of any wood-boring beetle, rather than one particular species. In the UK, the most common are the Common Furniture Beetle (Anobium punctatum), Deathwatch Beetle (Xestobium rufuvillosum), House Longhorn Beetle (Hylotrupes bajulus) and Powderpost Beetle (Lyctus brunneus). All invade and consume wood, and then leave when they have reached maturity.

How do I know if my property is affected?

Your woodwork may be harbouring woodworm without you knowing it. Wood can be infected with eggs or larvae without it being noticeable, and you may not discover a woodworm infestation for several years. It's a common misconception that woodworm only affects old properties, in fact it can cause damage to newly constructed buildings.

Tell tale signs of woodworm include:

  • Small round holes in your woodwork, similar to the holes in a dart board.
  • Fine, powdery dust around these holes (this is known as frass).
  • Crumbly edges to boards and joists.
  • Adult beetles emerging from the holes or present around the house.

Even if you can't see any holes, you might also find frass escaping from the back or underside of old furniture. Again this suggests active woodworm.

However, not all of these signs of activity are cause for concern. Holes and frass might just indicate a previous woodworm infestation, long since dormant. The following tips are to help you confirm whether you have a serious, current problem:

TIP 1

Not all woodworm are harmful - consult a professional entomologist to identify the woodworm before you decide on treatment. The British Pest Control Association offers an insect identification service.

TIP 2

Adult beetles are responsible for boring the holes when they exit the wood to breed. This happens between May and September, so a good idea is to block the holes during the winter by painting with a coat of emulsion, or applying masking tape. In the spring, you can check if any beetles have emerged and therefore determine whether you have active woodworm in your timber.

TIP 3

Test the humidity of your woodwork using a timber moisture meter. These cost about 50 but you can hire one from a hardware store. Insert the probe and you'll get an instant moisture content reading. A moisture content of 20% would be a cause for concern. Woodworm prefers timber with moisture content over 18 %, although it can tolerate moisture contents as low as 12 % for short periods. At lower moisture levels, however, the rate of colonisation tends to be low and infestation will die out with prolonged periods of reduced moisture levels. (Ref: Helen Sellars/Sophie Hale, Forest Research, Midlothian). You can assume that a reading of 11% puts you at very low risk of a woodworm infestation.

Measures to prevent woodworm infestation

  • Keep humidity levels low and ensuring wood is well-ventilated. See above for advice on checking moisture content of your timber.
  • Remove pieces of furniture or non-structural timber that are infested to avoid the woodworm spreading.
  • Install electric fly traps in loft spaces and under-ventilated areas to kill emerging adult beetles in the summer months, and thus reduce the threat of infestation.

 
 


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