Capricorn beetle in oak beams


I bought a derelict farmhouse 5 years ago. I have been renovating and finally got to making my ‘dream’ bedroom in what was an old hay loft above a cattle stall. The bedroom is everything i dreamt it would be. However I share this space with capricorn bettle larvae who are eating my oak beams!

I cleaned and sprayed all the oak framework 3 times before starting the renovation of this space. However the capricorn are very much alive and are driving me mad with their munching. I am also worrying about what structural damage they are doing. The oak is very strong where I have drilled in the injection plugs but one area has visibly been badly eaten.

I have literally poured, brushed, sprayed and injected
over 100l of xylophene into and onto the affected areas and the muching continues… I have found 21 dead capricorn bettle in the bedroom a few months after I started the treatment some 12 months ago but none since.

Does anyone have any advice what i should do next please.

Thanks in advance.

Welcome to the forum.
I’ve flagged someone that may help you, he’s a professional in this line of work @Rob_le_Pest


I absolutely would get in a professional before you end with structural disaster!

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Thank you for the replies. I sent a few messages to local professionals last night so fingers crossed I will hear back from someone soon.

Hi Katrina,
Firstly, welcome to France. If you’ve come from a sound town building in England and move to a dream barn conversion in France, the house will ‘sing’ differently, they are there to intentionally drive you crazy!

Ok, you need to STOP. On the tin is says 2 coats by pulverisation (spray) or paint. If you put 10 coats on it means you have wasted 8 times more product than required, The wood is not 10 times better protected. You have already proved that the product is working as you are finding dead larvae.

The capricorne larvae can live up to 5 years in the wood. They will only succomb when they emerge (eat) through the outer layers of the wood.

I assume the building is several hundred years old, and that it was vacant for some time before you bought it. Therefore it has survived that long and is unlikely to fall down tomorrow, hopefully!

If you know where they are chewing, try and hack them out as you have already been doing. Usually the inner core of the wood will be fine. If the wood is compromised, it can be braced.

Where in France are you? Can you post/pm some photos of the wood.

Calling an expert in, they will recommend one of 2 treatments; surface spray, you have already done that, so no need, or injecting, which in my opinion is unsightly and costs a minimum of 100€ + VAT per linear metre. Another member of SFN was recently quoted 27€K to injection treat a chalet in Savoire. They had done exactly the same as you, coat after coat of Xylophene/Xilix. I convinced them to save their money.

If you need any more advice or help, feel free to contact me.

Rob_le_Pest :blush:



Many thanks!

:blush: Rob :wink:


Hi Rob,

Thanks for taking the time to reply.

I’m in 71 Soane et Loire

Listening to the little munchers again :roll_eyes:

It was the bettles i found dead, not larvae.

I had a reply from 1 peat control company today who do not have any operations in my area :unamused: so that is a dead end. Still no contact from any others. Very much my experience here in France. I struggle to get any french tradesmen to provide a devis even when they have taken the time to look at my work.

My property is around 100 years old and was vacant for several years before I bought it. The area where the capricorn are is in an area which was never inhabited, not by humans anyway.

I bought a new wagner pump so will inject again when i can hear them. I’m worried to hack or drill them out for fear of causing more damage to the beam. They are in a huge oak beam so at least that is something. I can hear perhaps 4 of them .

Here are photos.

Thanks for any advice you have and can give.


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@KatrinaFrance Please PM me your postcode. I have asked for my national fournisseur for some reputable wood treatment specialists in 71.

It seems that you have all the kit. All rotten/eaten materiel should be removed before treatment, so if you think you’re going too fr with the excavations, a structural engineer might be useful to to have a look at it.

Alas no photos attached!


Here are the photos. I have PM’d you my address.



Will be totally gorgeous once the beasties are out !