It's late March 2014 and a new year for Death Watch Beetles. The tapping has resumed but so far I've only found 5 beetles. The tell-tale tapping resumed about 1 week ago which is earlier than last year which was mid April.
For the past 12 months I've been periodically spraying Kibosh using the long straw from a WD40 can, deep into exit wholes onto specific timbers. I will monitor these timbers closely to see whether there is a reduction in the number of beetles I find from these this year. The rationale for spraying into the holes is that some research has shown
that adult death watch beetles do not necessarily emerge from the
timber and can mate in cavities. Also adult females may reenter existing flight-holes and lay their eggs deep in the
timber. Therefore by spraying into the exit holes I may be killing larvae before they transform into adults. Spraying has shown that 80% of holes are single holes whereas 20% seem to have connections to other holes. A small percentage form a maze and the spray exits from other holes and crevices.
In addition to periodically leaving the dehumidifier running next to these timbers, I've also had a go at heat treatment.
One very expensive way to (maybe?) treat death watch beetle is to employ a specialist firm that wraps your house in a giant bubble and pumps hot air with carefully controlled low humidity air into your house to dry out the timbers and remove the vital moisture that the death watch beetles need. It's carefully controlled to stop the beams splitting. I havent got a clue how much this costs but looking pictures I found on the internet of what's involved, I wouldnt be surprised that a £30k+ price tag could be involved.
I opted for a simple route to see whether heat treatment works. I used a infra red heater to heat the surface of the wood on a particular beam to 60oC and left it exposed for a period of 1 hour. The theory is that death watch beetles die if they are exposed to temperatures of 55oC for more than 15 minutes. There doesnt however seem to be a consistent view on the internet of what the temperature should be or what the exposure time should be. Some reports say 47oC for 15 minutes whilst others suggest 55oC for 8 hours.
Unfortunately my mathematical ability to solve differential equations has long since passed - it would be useful to still be able to do this to calculate whether temperature expose has any real effect. The beetle larvae can be 1-2cm below the surface of the wood. Although the surface of the wood will reach the fatal 60oC, there's no guarantee how hot the wood gets several cm in. Wood doesnt heat up instantly and therefore there is a temperature gradient. The outside may be cold (one side of the wood faces the exterior) and so loses heat rapidly and another face may be laying on a brick sole plate acting like a huge heat sink so also doesnt get hot. Because of this the heat may quickly dissipate to a non fatal level. I tried a few experiments of pieces of wood that are not part of my house and it look like wood in free space takes over 1 hour for 5cm piece of wood to reach a similar temperature to the surface. I therefore guessed that exposing the wood for 1 hour would penetrate 2cm for wood which is attached to the fabric of the building. Since most holes seem to be in the 1-2cm deep category, I figured this would be adequate to kill most larvae beneath the surface.
By using a variety of techniques (including beetles munching their way through previously chemically treated wood) I am hopeful many of them will be killed off. It doesnt matter if it doesn't kill them all - by dramatically reducing the death watch beetle population, the population may naturally die off since the probably of finding a mate to keep the reduction cycle going, may be reduced.
In the coming weeks, I'll report on the quantities of beetles found.
Sunday, 30 March 2014
Wednesday, 10 July 2013
Get the death watch beetle treatment book
I decided to write an eBook documenting my experience was death watch beetles and my DIY approach to eradication given that the professional approach is still un-proven.
You can get my death watch beetle treatment book from Amazon.
On Friday 12th July 2013 and Saturday 13th July 2013 you'll be able to download it to your Kindle for free.
So what's in the book?
Why professional treatment methods may not be the best solution to your problem.
Steps you can take to encourage the decline of death watch beetle
Gain a better understanding of what you're up against and to understand the basic conditions that death watch beetles need to ensure their survival and how long you will have to fight these pests.
Armed with this information you are better informed whether to proceed with the expensive treatments from the "professionals" or whether a DIY treatment may be the solution to your problem.
You can get my death watch beetle treatment book from Amazon.
On Friday 12th July 2013 and Saturday 13th July 2013 you'll be able to download it to your Kindle for free.
So what's in the book?
Why professional treatment methods may not be the best solution to your problem.
Steps you can take to encourage the decline of death watch beetle
Gain a better understanding of what you're up against and to understand the basic conditions that death watch beetles need to ensure their survival and how long you will have to fight these pests.
Armed with this information you are better informed whether to proceed with the expensive treatments from the "professionals" or whether a DIY treatment may be the solution to your problem.
Wednesday, 29 May 2013
Decline?
The deathwatch beetles started knocking and emerging late this year. It was around the middle of April rather than late March.
I've been collecting the beetles and counting them. I think they are in decline. I would estimate on average I've collected 100 per week. They are still emerging now at the end of May but the knocking has pretty much stopped.
I've been studying where they are emerging from and have measured the moisture content of the wood.
When I bought the property it had a bit of a problem with damp on the dwarf wall which the sole plate rests upon. The company doing the damp treatment and woodworm treatment recommended tanking (covering in plastic) the interior wall. This has stopped the damp but I think has increased the deathwatch beetle problem. Rather than the water evapourating in the air, the water is now trapped in the brickwork and rising to the sole plate via capillary action.
The sole plate now has a nice supply of water to feed the deathwatch beetles.
Deathwatch beetles need a wood moisture content of at least 14% to survive. The moisture content of the wood at the boundary with the brickwork is 22%.
The exit holes are more dense near the boundary hence I think with hindsight that tanking was the wrong solution and would have also saved me a reasonable cost!
Some articles on the web suggest that the survival of deathwatch beetles is usually down to some building defect such as cracks, leaks or down-pipes. I've measured the water content of internal beams where it would be impossible for a building defect to allow water to ingress and the beams measure about 18%. So at a level where deathwatch beetles can survive.
The wood was treated when I bought the house and the majority of exiting beetles are being killed by the poison. I am straying into the exit holes with a long straw like sprayer, crawling insect killer which contains permethrin. This seems to be working too.
Why am I spraying when it's been treated? Well I've discovered that traditional wood worm treatment is a surface spray and penetrates the wood only a few millemetre. Occassionally I find very deep deathwatch beetle exit holes which are 2-3cm deep.
Not all beetles exit to reproduce. It's been recently discovered that mating can occur in the holes and therefore the lavae continue munching on untreated wood.
By spraying into the holes, the poison is delivered deep in the wood and onto any beetles or lavae in there. I don't know if this strategy is working but it intuitively seems a better approach than relying on them exiting.
Square wood has four faces. When the building was treated only the exposed faces were sprayed so in some cases only one face (25%) of the wood has been treated.
I don't know whether all the beetle tapping allows these pests to emerge on the face - if not then I only have 25% protection!
I've got the dehumidifier running when my wife is not around to complain about it. That should help in drying out the wood and removing that all important water for the death watch beetle survival.
Beams by radiators have a moisture content of 0% ! And no sign of deathwatch beetle either. Removing moisture is clearly a good strategy.
So in summary I think they are declining compared to previous years but the emerging season hasnt finished yet. We are now 6 complete years after they have been sprayed which is cited as the breeding cycle so next year hopefully will see a significant decline in beetles.
I've been collecting the beetles and counting them. I think they are in decline. I would estimate on average I've collected 100 per week. They are still emerging now at the end of May but the knocking has pretty much stopped.
I've been studying where they are emerging from and have measured the moisture content of the wood.
When I bought the property it had a bit of a problem with damp on the dwarf wall which the sole plate rests upon. The company doing the damp treatment and woodworm treatment recommended tanking (covering in plastic) the interior wall. This has stopped the damp but I think has increased the deathwatch beetle problem. Rather than the water evapourating in the air, the water is now trapped in the brickwork and rising to the sole plate via capillary action.
The sole plate now has a nice supply of water to feed the deathwatch beetles.
Deathwatch beetles need a wood moisture content of at least 14% to survive. The moisture content of the wood at the boundary with the brickwork is 22%.
The exit holes are more dense near the boundary hence I think with hindsight that tanking was the wrong solution and would have also saved me a reasonable cost!
Some articles on the web suggest that the survival of deathwatch beetles is usually down to some building defect such as cracks, leaks or down-pipes. I've measured the water content of internal beams where it would be impossible for a building defect to allow water to ingress and the beams measure about 18%. So at a level where deathwatch beetles can survive.
The wood was treated when I bought the house and the majority of exiting beetles are being killed by the poison. I am straying into the exit holes with a long straw like sprayer, crawling insect killer which contains permethrin. This seems to be working too.
Why am I spraying when it's been treated? Well I've discovered that traditional wood worm treatment is a surface spray and penetrates the wood only a few millemetre. Occassionally I find very deep deathwatch beetle exit holes which are 2-3cm deep.
Not all beetles exit to reproduce. It's been recently discovered that mating can occur in the holes and therefore the lavae continue munching on untreated wood.
By spraying into the holes, the poison is delivered deep in the wood and onto any beetles or lavae in there. I don't know if this strategy is working but it intuitively seems a better approach than relying on them exiting.
Square wood has four faces. When the building was treated only the exposed faces were sprayed so in some cases only one face (25%) of the wood has been treated.
I don't know whether all the beetle tapping allows these pests to emerge on the face - if not then I only have 25% protection!
I've got the dehumidifier running when my wife is not around to complain about it. That should help in drying out the wood and removing that all important water for the death watch beetle survival.
Beams by radiators have a moisture content of 0% ! And no sign of deathwatch beetle either. Removing moisture is clearly a good strategy.
So in summary I think they are declining compared to previous years but the emerging season hasnt finished yet. We are now 6 complete years after they have been sprayed which is cited as the breeding cycle so next year hopefully will see a significant decline in beetles.
Wednesday, 6 June 2012
Silence
I must get more scientific about these pesky beetles.
At the end of May 2012 I noticed the tapping stopped however beetles are still emerging. In fact I would say the number of beetles emerging has increased despite the tapping stopping. Over the long Jubilee weekend, I found about 20 beetles per day. Given the tapping is supposed to be how they find their mates it is interesting that so many death watch beetles are emerging (and still drilling their little holes) without tapping.
If they are still around next year (I'm always hopeful the colony is dying off), I think it would be useful to measure beetles collected per week as well as logging outside temperature and rainfall. Given the weather the week before was really hot and then cooled down and started raining, maybe these pets like to emerge when it is wet and cool rather than hot. It would kind of make sense if that is the case since the eggs/lavae rely on moisture in the wood. If it has been raining then wet wood would help them survive early on.
I was also thinking about alternative non chemical methods of treating death watch beetles. Given spiders are a native pest, injecting spider eggs into the holes would be a good way to control them. It wouldn't work for me though - my wife hates spiders.....
At the end of May 2012 I noticed the tapping stopped however beetles are still emerging. In fact I would say the number of beetles emerging has increased despite the tapping stopping. Over the long Jubilee weekend, I found about 20 beetles per day. Given the tapping is supposed to be how they find their mates it is interesting that so many death watch beetles are emerging (and still drilling their little holes) without tapping.
If they are still around next year (I'm always hopeful the colony is dying off), I think it would be useful to measure beetles collected per week as well as logging outside temperature and rainfall. Given the weather the week before was really hot and then cooled down and started raining, maybe these pets like to emerge when it is wet and cool rather than hot. It would kind of make sense if that is the case since the eggs/lavae rely on moisture in the wood. If it has been raining then wet wood would help them survive early on.
I was also thinking about alternative non chemical methods of treating death watch beetles. Given spiders are a native pest, injecting spider eggs into the holes would be a good way to control them. It wouldn't work for me though - my wife hates spiders.....
Monday, 23 April 2012
Measurement
After realising I had a problem in 2008, my experiments with boron led me to think that sitting and wait for the chemicals to do their job might be my best strategy.
In 2009 I started recording my observations. I did intend to log how many beetles I found each week with a view to publishing my findings so I could see when the beetles were most active and to confirm that over time they were dying out. By killing the beetles when they exit the wood, the breeding cycle is broken.
So I set about collecting beetles whether dead or alive. By collecting them and putting them in a tin, they weren't finding mates and laying eggs on the beams.
In 2009 I collected around 500 beetles from the house.
I couldnt find any information on the internet to indicate how bad, a bad infestation is. One article suggested in a bad infestation you can see them popping out the wall. So providing a number helped me get a feel for the scale of the problem.
Of the 500 I collected about 90% were dead - the poison had clearly worked but some were very much alive and survived weeks in my tin of death. They had not been exposed to the poison. How come? Well - chemical treatment of wood only treats exposed surfaces. For my beamed walls only 1 surface has been treated - in other words only 25% of the exposed surfaces have chemical treatment. What I really need to do is strip away all the plaster between the beams and have 2 more surfaces treated. An expensive activity and not something I would want to do. It might be worth doing long term to improve the insulation performance of my old leaky house.
The beetle collection resumed in 2010. A similar number was collected.
In 2011, the number of beetles was down to about 350 beetles - relatively few beetles emerged but there was a frenzy week in May when about 150 of the 350 beetles emerged.
So far 2012 has seen fairly low numbers of beetles. Currently about 50 collected so far.
I have resorted to some other pest control methods. I have a de-humidifier to remove moisture in the house and hopefully dry out the beams. It doesn’t look like it has had a a massive effect on the moisture levels in the beams but then a few percent fall can be life or death for the beetles. The problem is my wife doesn’t like having the dehumidifier on.....
I have also adopted a chemical treatment regime of my own. I have a spray can of Kibosh insect killer. I have replaced the nozzle with a straw nozzle from a can of WD40. This allows me to insert the straw deep into the death watch beetle holes and spray the poison in. Whenever I find the frass or a death watch beetle, I spray into the new hole.
Why do this? Firstly not all beetles will emerge - they can find mates in their own tunnels in the wood. Not all holes are tunnels but some are. By spraying in, the poison is sprayed deep into the timber rather than just the surface of normal chemical treatment. Once when I did this it caused a flurry of beetles (about 5) to exit from other holes.
In 2009 I started recording my observations. I did intend to log how many beetles I found each week with a view to publishing my findings so I could see when the beetles were most active and to confirm that over time they were dying out. By killing the beetles when they exit the wood, the breeding cycle is broken.
So I set about collecting beetles whether dead or alive. By collecting them and putting them in a tin, they weren't finding mates and laying eggs on the beams.
In 2009 I collected around 500 beetles from the house.
I couldnt find any information on the internet to indicate how bad, a bad infestation is. One article suggested in a bad infestation you can see them popping out the wall. So providing a number helped me get a feel for the scale of the problem.
Of the 500 I collected about 90% were dead - the poison had clearly worked but some were very much alive and survived weeks in my tin of death. They had not been exposed to the poison. How come? Well - chemical treatment of wood only treats exposed surfaces. For my beamed walls only 1 surface has been treated - in other words only 25% of the exposed surfaces have chemical treatment. What I really need to do is strip away all the plaster between the beams and have 2 more surfaces treated. An expensive activity and not something I would want to do. It might be worth doing long term to improve the insulation performance of my old leaky house.
The beetle collection resumed in 2010. A similar number was collected.
In 2011, the number of beetles was down to about 350 beetles - relatively few beetles emerged but there was a frenzy week in May when about 150 of the 350 beetles emerged.
So far 2012 has seen fairly low numbers of beetles. Currently about 50 collected so far.
I have resorted to some other pest control methods. I have a de-humidifier to remove moisture in the house and hopefully dry out the beams. It doesn’t look like it has had a a massive effect on the moisture levels in the beams but then a few percent fall can be life or death for the beetles. The problem is my wife doesn’t like having the dehumidifier on.....
I have also adopted a chemical treatment regime of my own. I have a spray can of Kibosh insect killer. I have replaced the nozzle with a straw nozzle from a can of WD40. This allows me to insert the straw deep into the death watch beetle holes and spray the poison in. Whenever I find the frass or a death watch beetle, I spray into the new hole.
Why do this? Firstly not all beetles will emerge - they can find mates in their own tunnels in the wood. Not all holes are tunnels but some are. By spraying in, the poison is sprayed deep into the timber rather than just the surface of normal chemical treatment. Once when I did this it caused a flurry of beetles (about 5) to exit from other holes.
The Research Phase
After the disappointing conversation with the wood worm treatment company (basically saying come back in 5 years time if what we've done hasnt had any effect), I set off to find out more about my illegal occupants.
Death watch beetles live in hard woods such as oak. The wood needs to have suffered some disease and the wood needs moisure content for the beetles to survive. The lavae are laid on
the wood and they burrough into the wood where they happily munch the wood until they mature. This typically takes 7 years. If the wood is not very moist they grow slowly and might take 12 years to mature. When they mature, they metamorphose into adult beetles. Adult beetles emerge from the wood in order to mate and lay more lavae eggs. The adults cant feed but can chew - they can live several weeks giving them enough time to find a mate and lay some eggs.
There is remarkably little information on the Internet about deathwatch beetles. As fear started to take over and I was began to wonder whether my house would fall down in the 5+ years whilst I waited for the bugs to die, I read everything I could find about these pests. Did I have a really bad infestation or was my colony simply ticking away and would slowly die out anyway?
Most infestations of death watch beetle have been there since the house was built. It seems mine have probably been there for hundreds of years and the house is still standing.
The information available about eradication seemed to be very much about what I had already done which is chemical treatment. I found some anecodatal stories on the Internet from deathwatch beetle sufferers who seems very relaxed about them - accepting their existence as being almost part of the charm of living in an old house. Personally I want to kill them all off!
I looked at boron paste and pellets. Normal chemical treatment uses some pretty nasty chemicals whilst boron is harmless to humans but poisonous to beetles. So I bought some Boron has started drilling some holes into my heavy oak beams to insert the boron pellets. After drilling several holes with the drill straining to makes holes into the aged oak I came to the conclusion that maybe I was doing more damage in a few seconds than the beetle would do in 7 years. So I topped....The boron paste doesnt need holes drilled but it discolours the beams - dilemma do I ruin the natural charm of my oak beams or smother them with boron paste....
Other articles suggested that death watch beetles need around 17-20% moisure content for the beetles to survive. So time to invest in a moisture meter. Well it seems my beams are arund 20% moisure content. Those near radiators are very dry - 0%.
Another article suggested that there is always a cause of the death watch beetles - they need to get moisure from somewhere and that is usually a leaking roof, window frame or some other building defect. I accept the argument however my house suggests this clearly cannot always be the case. I have deathwatch beetle on internal beams that cannot possibly be getting water from external sources, I have to admit that the beetles are more active on external beams.
This leads me to another discovery. When I bought the house I had damp. The company I employed solved the problem by tanking the sole plate wall. With hindsight I've discovered this probably wasnt the best solution. By tanking the brick sole plate wall it does mean moisture is trapped in the brick work whereas previously it would evapourate into the house (causing damp). Now the moisure on the brickwork is higher, the sole plate beam is now exposed to higher moisture content increasing the survival prospects for my noisy insects.
Death watch beetles live in hard woods such as oak. The wood needs to have suffered some disease and the wood needs moisure content for the beetles to survive. The lavae are laid on
the wood and they burrough into the wood where they happily munch the wood until they mature. This typically takes 7 years. If the wood is not very moist they grow slowly and might take 12 years to mature. When they mature, they metamorphose into adult beetles. Adult beetles emerge from the wood in order to mate and lay more lavae eggs. The adults cant feed but can chew - they can live several weeks giving them enough time to find a mate and lay some eggs.
There is remarkably little information on the Internet about deathwatch beetles. As fear started to take over and I was began to wonder whether my house would fall down in the 5+ years whilst I waited for the bugs to die, I read everything I could find about these pests. Did I have a really bad infestation or was my colony simply ticking away and would slowly die out anyway?
Most infestations of death watch beetle have been there since the house was built. It seems mine have probably been there for hundreds of years and the house is still standing.
The information available about eradication seemed to be very much about what I had already done which is chemical treatment. I found some anecodatal stories on the Internet from deathwatch beetle sufferers who seems very relaxed about them - accepting their existence as being almost part of the charm of living in an old house. Personally I want to kill them all off!
I looked at boron paste and pellets. Normal chemical treatment uses some pretty nasty chemicals whilst boron is harmless to humans but poisonous to beetles. So I bought some Boron has started drilling some holes into my heavy oak beams to insert the boron pellets. After drilling several holes with the drill straining to makes holes into the aged oak I came to the conclusion that maybe I was doing more damage in a few seconds than the beetle would do in 7 years. So I topped....The boron paste doesnt need holes drilled but it discolours the beams - dilemma do I ruin the natural charm of my oak beams or smother them with boron paste....
Other articles suggested that death watch beetles need around 17-20% moisure content for the beetles to survive. So time to invest in a moisture meter. Well it seems my beams are arund 20% moisure content. Those near radiators are very dry - 0%.
Another article suggested that there is always a cause of the death watch beetles - they need to get moisure from somewhere and that is usually a leaking roof, window frame or some other building defect. I accept the argument however my house suggests this clearly cannot always be the case. I have deathwatch beetle on internal beams that cannot possibly be getting water from external sources, I have to admit that the beetles are more active on external beams.
This leads me to another discovery. When I bought the house I had damp. The company I employed solved the problem by tanking the sole plate wall. With hindsight I've discovered this probably wasnt the best solution. By tanking the brick sole plate wall it does mean moisture is trapped in the brick work whereas previously it would evapourate into the house (causing damp). Now the moisure on the brickwork is higher, the sole plate beam is now exposed to higher moisture content increasing the survival prospects for my noisy insects.
Wood treatment
My discussion with the woodworm treatment starts with I think I have a new infestation of death watch beetle. I am then asked when they treated the property - I naievely thought this was so they could look up the records....
The chemicals used to treat timber, and my 17th century cottage has a lot of oak beams which holds the house up, only penetrates a few millimeters into the wood. Think of the woodworm living in the beam as now encased in a lethal tomb. When the deathwatch beetle decide to exit (March to June each year), they then munch their way through the poison wood which kills them. The problem is that deathwatch beetles can live a long time - it can take between 7 and 12 years for them to mature and decide to escape.
The annoying scratching I was hearing was the male beetle banging his head against the inside of the wood to attract a mate.
So here I am thinking I've had the wood treated to kill the beetles only to find that these squatters are living in my house and I cant evict them for upto another 10 years.
The chemicals used to treat timber, and my 17th century cottage has a lot of oak beams which holds the house up, only penetrates a few millimeters into the wood. Think of the woodworm living in the beam as now encased in a lethal tomb. When the deathwatch beetle decide to exit (March to June each year), they then munch their way through the poison wood which kills them. The problem is that deathwatch beetles can live a long time - it can take between 7 and 12 years for them to mature and decide to escape.
The annoying scratching I was hearing was the male beetle banging his head against the inside of the wood to attract a mate.
So here I am thinking I've had the wood treated to kill the beetles only to find that these squatters are living in my house and I cant evict them for upto another 10 years.
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