Roof timbers - Death watch beetle / Capricorn

I am wondering if anyone has experience of treating roof timbers for Capricorn beetles - a sort of French-speaking deathwatch without the tapping!, I have been quoted 5300 euros for piercing the big ones for perfusion and spraying gel on the smaller ones. It doesn't sound too unreasonable but I have no experience to draw from?

Good comments Brian. Thanks.

PS I made a typo error: Borax is "Sel de bor". A useful preventative treatment but not a preservative. Cheap and relatively harmless to humans.

Addenda: The important thing with wood in buildings is to keep the wood dry and well ventilated. The wood eating creatures love stagnant air and sweet moist timber.

James: On plywood, no idea but perhaps this is a clue. Nearby is a sawmill where we buy construction timber. People come from a long way to buy there so I guess they are good. Anyway, when I had them cut me an oak window joist I was asked if I wanted it treated or not, advised it is best to. I asked why it should be treated. In response I was taken to one of the large piles of wood dust and shavings. They make it up into pellets and chips for stoves. Anyway, he delved into a corner and brought out a handful of wood dust, separated it a bit with his finger and there were four larvae... He said they eat anything as long it is wood. I asked if that means wood chips are full of it. The adhesive that bonds it kills them he said. So, plywood being glued together is perhaps the same, thus at a guess no.

Generally: Further to what I said below about charlatans. There are answers they should not give. I have read about people finding stag beetles in their houses, the exterminators saying they need to be got rid of. To begin with, they are about six times the size of DWB, then their larvae feed on decaying and dead wood and roots which are outside. The larvae are 8cm, sometimes 10cm, long and as thick as a thumb with an orange head, nothing like capricorn beetles at all. Stag beetles are also an endangered species in several European countries and protected, eradicating them is forbidden. In every sense, despite their size and 'antlers' they are totally harmless. Do not let the 'experts' con you into believing they are 'large capicorn' so must be done away with.

Will DWB eat plywood?

There are plenty of charlatans out there who will um and ah and say that perfectly sound, healthy and uninfected wood needs treatment. There are only death watch beetle larvae if the wood has experienced prior fungal decay which can also be in new timber. Whatever the state of the wood, only tapping near holes so that dust falls, then really cleaning out with a vacuum cleaner until none falls helps. If after 24 hours there is new dust fall then you may have them. There are also several other beetles and woodlice that cause similar effects. If people have cats, dogs, birds and other small pets then Xylophenes can be very dangerous for them, harmful to human beings as well.

All i would say is be wary of Xylophenes. They can continue to exude noxious fumes which are really not good for the human creature. The other thing to be wary of is that there are number of spurious companies out there ripping people off so check the credentials of the company and find out what kind of guarantees there are. A good company will comply with French norms and provide a ten year guarantee. Get comparative quotes.
Your quotation sounds very high unless it is a huge house. The injection treatment is the only way you are going to eradicate Capricorn and this definitely needs to be done professionally since it must be done with the correct product and at high pressure. Impossible to do on a diy basis without a lot of expensive kit. A good company will know what it is doing.
Preventative treatment the best. The Capricorn beetle is often in freshly felled timber and is often built into the house at the outset. So when replacing timbers try and use partially dried timber and check it over well before it goes in. It is a good idea to use borax as a harmless preventative treatment (self de bor available at most good builder’s yards) rather than dangerous Xylophenes.

A bit more DWB Beetle. Source BPCA

Death-watch Beetle (Xestobium rufovillosum). Five to nine millimetres in length, elongate dark mottled brown beetle, found out of doors from spring to early summer. Decaying branches and trunks of oak and willow are favoured hardwood trees. Oak is most commonly infested indoors, hence the association with old churches. The complete life cycle may take anything up to four and a half years. The adult emergence holes are usually about four millimetres in diameter. Significant weakening of major structural timbers takes many years of infestation.

The services of an experienced timber pest-control specialist are generally required to carry out treatment to control this pest.

Infestations already present in wood are unlikely to be controlled even by specialists but the timber can be treated with approved products to prevent the establishment of new generations of beetles. Source BPCA

A decent pressurised sprayer price varies but if you can afford a metal/inox one it's a bit of kit for life but are about £260 from the UK, and Xylophene from your local bricolage 95€ for 20 litres in my opinion is as effective as injecting. A DIY job a darn site cheaper than 3-5€K being banded around.


Hi James

I'm based literally in the centre of France (Cher) but I cover all areas, subject to the dreaded "déplacement" That can be pricey however I offer free advice whenever possible on Survive France, PM.

Kind regards


DAPA diplomé

What area do you cover Robert? I need some critters killing.


If this gets edited out by the moderatos I fully accept and understand, my aim is to inform and assist in the control of nuisibles.

I use a professional version of Xylophene. It is not available to the general public and it used to treat all wood munching critters, including termites (which requires a separate diploma). A more diluted version of Xylophene can be bought from your local bricolage where it will cost less than 100€ for 20 litres, It might be worth giving that a bash first! It also comes with a 10 year guarantee.

Injecting each hole takes a long time and is therefore expensive, effective treatment can be obtained using a 6 bar "pulverisateur" or by painting it on with a pasting brush.

Happy to discuss further by PM if need be.

Good luck


Thanks very much Roger. -Yours sounds to have a little more length of beams but also it is 6 years later. So it looks as if that price is reasonable although not very welcome in the run up to Noel!!

The barn we converted into the hotel was fully treated by CPB in Pau in 2007. We had completely stripped it out to just roof, beams and walls. It's a 2-storey 1830-built stone barn with oak woodwork, 29 x 6 metres. They charged us 5738 euros and it has a 10-year guarantee. (Capricorn is the main threat in this area - 64)

Sorry, it was part of the whole renovation!

Yes Jane -they were new to me and I also knew that termites were unlikely. Do you remember any ideas of what you paid?

When I first saw an adult Capricorn beetle I took a 'photo of it instead of squashing it flat. Never seen anything like it before. Unfortunately they were munching on our beams in the older part of our house.

The beams were treated by the carpenters doing the work, but we keep an eye out for any activity.

When we bought the house we were told that there were not any termites in Saone-et-Loire, they didn't mention capricorns!

Phew, best of luck though, any indecision and the wee beasties are effectively cheering and eating on...

PS 10 meters square

Thanks Brian -it is actually just the roof area there is very little timber in the rest of the house

Go for it. The longer you leave it the worse it gets. When we moved in the beams had been treated after a termite invasion a few years earlier, we still have a couple of beams and some floor to replace, but when wood dust started to fall and we got locally recommended people in, had quotes and all, we were warned that every week we spent thinking about it meant their larvae were munching their way through more wood. We now have a very expensive cast concrete floor in our kitchen because of indecision and the treatment should have been done earlier, maybe two months or thereabouts, for which we paid...

I am not sure what your quote describes but our entire treatment was certainly far more than that and entailed us going into a local gîte for several days. I looked in to see what was going on and it was certainly not as you recall, plugs like rawlplugs were inserted with an insecticide in them (still there to see although long since doing nothing) and some kind of liquid injected at regular intervals. It cost a bit more than your quote, but then it was the entire house. Then came the floor...