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.....
Wednesday 6 June 2012
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.
The Journey to DeathWatch
I bought my 17th century timber framed cottage in August 2006. The survey highlighted the property had some active woodworm and evidence of death watch beetle holes.
Being totally naieve about deathwatch beetle I simply arranged for a company to come treat the property along with fixing the damp problem at the same time.
Fast forward to March 2007 and I could hear some scratching noise in the loft at night. I suspected mice so put traps up there and guess what - I never caught a mouse. The scratching continued until early June. As the house was in turmoil with renovation, I didnt notice the death watch beetles around the property.
A year passes and in March 2008 the annoying night-time scratching resumes. This time I investigate since the house is no longer in chaos and layered with building dust. My suspicions are aroused as I notice the frass (dust when woodworm exit the wood) and the occassional insect lying around the house. So off I go and contact the company that did the wood treatment. And here is where my journey starts I inadvertedly become a bit of an expert on deathwatch beetles.
Being totally naieve about deathwatch beetle I simply arranged for a company to come treat the property along with fixing the damp problem at the same time.
Fast forward to March 2007 and I could hear some scratching noise in the loft at night. I suspected mice so put traps up there and guess what - I never caught a mouse. The scratching continued until early June. As the house was in turmoil with renovation, I didnt notice the death watch beetles around the property.
A year passes and in March 2008 the annoying night-time scratching resumes. This time I investigate since the house is no longer in chaos and layered with building dust. My suspicions are aroused as I notice the frass (dust when woodworm exit the wood) and the occassional insect lying around the house. So off I go and contact the company that did the wood treatment. And here is where my journey starts I inadvertedly become a bit of an expert on deathwatch beetles.
Subscribe to:
Posts (Atom)