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How to Stop Borer Eating Your Home

How to Stop Borer Eating Your Home
How to Stop Borer Eating Your Home

Protect your largest investment.

There are up to 7 species of wood-boring insect in New Zealand that might attack the timbers of your home or other buildings. The most common of these is the Common House Borer (Anobium punctatum) also known as Woodworm in other parts of the world. A close relative, is the Native House Borer (Leanobium flavomaculatum) is rarely distinguished from the Common Borer and may be the more common.

The life cycles of these insects are similar. Adult females lay up to 100 eggs on bare timber or in old flight holes. The eggs hatch after 4-5 weeks and the larvae bore through the wood, eating it and using yeasts in their stomachs to help break down cellulose in the wood. After 3-4 years the larvae will pupate in a chamber near the surface, then 4-8 weeks later the adult exits the wood by eating its way to the surface creating a 'flight hole'. It mates and begins the life cycle over again. The flight holes are approximately 2mm in diameter for Common Borer and 3-4mm for native borer.

It is important that a thorough survey is carried out to ascertain the extent of any infestation. It is frequently the case that a few flight holes are visible on the exterior of painted weather boards, however when the boards are examined more closely the interior of the timbers are badly damaged and many flight holes are present on the interior surface.


Treatment of timbers to remove borer infestation is the same for whichever species is present.

  1. Treat any bare wood with Kiwicare NO Borer fluid. This insecticide will penetrate deep into the timber and will kill larvae as they eat the wood and prevent adults laying eggs on the surface. In normal circumstances this will protect the wood for many years.
  2. Inject flight holes with Kiwicare NO Borer Injection fluid. This comes in a handy aerosol supplied with a nozzle for fitting into the holes. The aerosol forces insecticide into the labyrinth created by the borer larva killing any larva in the labyrinth or nearby. It also prevents adult beetles laying eggs in the flight hole.
  3. During each flight season (October-May) set off Kiwicare NO Borer Borafume Bombs in roof voids and sub-floor areas. These knock down adult beetles that would lay eggs on the exposed timbers here and give protection to the surface of the timbers.
  4. Borer prefer timber that has some moisture in it. Ensure that your sub-floor is dry and well ventilated. Check for plumbing leaks and unblock all air vents. Check for leaks in the roof and if you have old terracotta or concrete tiles check that they are well sealed. These can act like sponges soaking up water and increasing the relative humidity of roof voids. Kiwicare produce a silcone terracotta sealant called NO Leaks that can be used to seal tiles and walls.

This combination of treatment will protect your home and your investment .

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Hello, Don't panic. This is


Don't panic. This is not a problem. Although NO Borer Concentrate does not mix easily with water, as it is formulated to mix with turps or kerosene, the water will not affect the product. The concentrate will still provide protection from borer. It just may not have penetrated as far into the wood and so will not last quite as long. The water will soon dry off leaving the borer protection behind and will not attract borer.

If the area to be treated is small Kiwicare make a ready to use NO Borer Fluid which does not require use of additional solvent.

Hi I have mixed Kiwicare NO


I have mixed Kiwicare NO Borer Concentrate with water instead of turps and applied to some bare timber affected by borer, what should i do now? I am afraid the water will attack more borer? Thanks.

Turpentine and kerosine are

Turpentine and kerosine are not 'highly toxic' but should of course be used with reasonable care. As with many solvents they should not be used in confined, unventilated spaces with a fine mist or where there are high temperatures. But used in well ventilated areas and using a coarse spray, paint brush or roller they pose little or no risk. Turpentine is, after all, used frequently as paint thinners.

I regularly recommend professional borer control companies and technicians that are members of PMANZ for those people that want a warranty for peace of mind and to accompany documentation on sale or purchase of property. Kiwicare is an associate member of PMANZ.

As with painting ones house it is a question of cost, time and ability to DIY.

Interesting comments on the

Interesting comments on the use of solvents for borer control. Regardless of the pro's and con's they do smell are are highly toxic within themselves. The fact of the matter is the average homeowner cannot effectively control borer, borer bombs have been around since borer and we still have borer! The use of a registered borer control technician through a reputable company is the best way to deal with borer. These companies will warranty their treatments for many years which will give the homeowner peace of mind and also add value if selling the house in the future.

Hi i am a licensed timber

Hi i am a licensed timber pest technician ,if you would like some ideas on treatment or costs for a professional treatment send me an email im sure we can help you

Treating a relocatable house

Treating a relocatable house for borer.

Before or during relocation is an ideal time to treat a house to protect it from borer.

It is possible to tent a house and fumigate it with methyl bromide to eradicate all borer. This is, however, almost never done because of the costs, regulations and the fact that it gives the house no ongoing protection. It could get an infestation again next season.

The house can normally be more easily treated while it is awaiting transport or after transport and when it is awaiting setting on foundations. Many of the more difficult to reach timbers (sub-floors, roof cavities, etc.) will be exposed and the effective long term treatment with borer fluid in turps or kerosene will not have the disadvantage of lingering smell for occupants; because there aren't any. Also, the interior of the house is easier to treat because of the lack of furniture fixings and fitting that would otherwise make full treatment more difficult.

To sum up, you should be able to treat the house more effectively and more cheaply during relocation than a house still in position giving the greatest and longest term of protection.

We are looking at a

We are looking at a relocatable house. There are signs of borer in external weatherboards, window framing inside, old signs in the polished t&g flooring, and underneath in joists. Can the whole house be enclosed in something and effectively fumigated where it is stored? Thanks

sorry i did not mean

sorry i did not mean (exterior) spray i meant to say (residual) low odor spray.

Hi after its fumigated i

Hi after its fumigated i would treat the timber with a residual chemical with an exterior spray, i would get the room treated and may be the house feel free to email me if you need help thanks

You can deal with the borer

You can deal with the borer in your bed slats yourself using NO Borer fluid and/or injecting the holes with aerosol NO Borer Injector. There will be a slight smell for a few hours. It will not linger long. A water based NO Borer trigger spray will have less smell and will be sufficient for your bed slats. Check out the website borer page for more information.

You can get the bed fumigated with methyl bromide by a licenced fumigator. This will kill all the borer in the slats but not give nay ongoing protection.

your timber could be

your timber could be fumigated in a container with methyl bromide, the room with the borer and mattress could be mist with Nuvos by a suitably qualified pest control technician. hope this helps

We have a bed borer problem

We have a bed borer problem - to our horror we have just discovered that all the slats of our 10 year old fixed-slat bed are covered in borer holes, how is best to treat the wood and will we have to treat our mattress as well? We last shifted five years ago, are in a five year old home and not too happy that we've been sleeping on top of the little critters possibly for the last five years?! We are keen not to have strong smells lingering after treatment so wondering what is best option please?

Great advise! yes boron also

Great advise! yes boron also has a down side it is not residual and will wash of. Using a Termicide with water as the carrier can give approx 10 year or more depending on the concentrations used, protection in areas where there is no UV and the surface is not exposed to the elements works well, I have discussed it with the manufacturers who supply a timber merchants in Australia who treat timber in a similar method and they give it 50 years i was told! Water is a good carrier also and should not be over looked. I have discussed the use of water or kero with chemical engineers and i have learned some very interesting things as to how the chemical particles are separated further apart when using kero as it takes it deeper into the timber and could could diminish the chemicals effectiveness, a bit in depth here to discuss. A good alternative is an oil, obviously not just any oil but a particular kind if you are worried about saturation, i have also done my own field research from jobs treated over a long period of time and have seen what works best. Sorry no trade secrets given away here! lots of laughs.

There is some discussion

There is some discussion below regarding the use of diesel or kerosene as carriers for insecticides when treating timber for borer.

Diesel is not recommended by Kiwicare for use with its borer products. Kerosene is recommended for use as it gives excellent penetration of timbers to give the longest term protection. But it should not be used in confined spaces without good ventilation and personal protective equipment, and the creation of mists should be avoided. Low pressure sprayers can be used but if ventilation is poor then use of a brush or roller will prevent mists.

I have carried out many professional borer control treatments with this and similar products over the last 30 years. Common sense has meant I have never encountered any of the problems suggested.

However, I did change the methodology used by one of NZ's largest pest control companies to the use of di-sodium octaborate (boron) because used properly it is effective but it does not result in the smell associated with the use of kerosene or turps. Borate does have to be applied with low pressure, high volume equipment to get sufficient saturation of the timber for good control and is not normally an option for the DIYer who wants to control the borer in his or her home.

Also you miss understand

Also you miss understand what they mean by breathing apparatus, it is not a mask like a face mask which you suggest, it must be a separate air supply either air tanks, ie like we use when we fumigate with cyanide disks or methyl bromide or an outside uncontaminated air supply.

i also point out this point

i also point out this point from shells info you missed regards you comment:

Precautions Under working conditions mists can occur at any temperature. It is therefore necessary to take precautions to avoid breathing any vapour or mist by using, for instance, air breathing apparatus, ventilation and extraction fans to remove mists and vapour from the working areas.

I would suggest any one

I would suggest any one intent on spraying in any confined space talk to the shell representative regards this use of a petroleum ie diesel, kerosene product before they use it in this way. I talked to them and they said under no circumstances should it be used under a house or in a roof void ie enclosed area in this manner! Be careful, if you give the wrong advise and something goes wrong even if you have public liability insurance it wont replace there life or brain cells. When i worked for some other company's in my younger years, i did suffer from severe headaches after spraying these products, i now know it was from a lack of oxygen. i was lucky that was all! I also used commercial equipment for spraying so the jobs where quick so mixed with luck i survived minus some brain cells - lots of laughs. I would never send any one to do that! I suggest before any advise is given maybe try it your self 1st - No just kidding i wouldn't suggest that.

Thank you. Kerosene and

Thank you.

Kerosene and dieseline (diesel) do not form high vapour concentrations at normal temperatures so "their vapour pressures are too low to pose these hazards under normal conditions."

Kerosene and diesel, as the Shell website states are "less likely to produce as high vapour concentrations as gasoline they are very prone to the formation of mists," So precautions including wearing a mask to prevent inhalation of mist particles is a normal precaution.

And the statement on contact is relevant to people who "continually handle petroleum products." It is still recommended to wear personal protective equipment while treating the borer in a house with kerosene, turpentine or any other borer product.

Hi this is directly copied

Hi this is directly copied from shell nz web site: Vapours and Gases Gasoline, hydrocarbon solvents and LPG gases are the most hazardous petroleum products at normal temperatures and pressures as vapours create a fire risk, and they can build up very rapidly in poorly ventilated areas, creating a risk of asphyxiation for people working in the area. The problem, though potentially severe, diminishes through kerosines, diesoline, fuel oil and lubricants, as their vapour pressures are too low to pose these hazards under normal conditions.

Mists While kerosine, diesoline, fuel oil and lubricants are less likely to produce as high vapour concentrations as gasoline they are very prone to the formation of mists as a result of their dispersion in air by mechanical processes. Mists are regarded as toxic by inhalation as the micro-droplets can coalesce on the lung surfaces and prevent extraction of oxygen from the air by creating a barrier.

Precautions Despite the variation that exists between products, under poor ventilation and high temperatures vapour can occur with all products, and under working conditions mists can occur at any temperature. It is therefore necessary to take precautions to avoid breathing any vapour or mist by using, for instance, air breathing apparatus, ventilation and extraction fans to remove mists and vapour from the working areas.

First Aid Symptoms, which occur if vapour or mist is inhaled, include irritation of the nose and throat, nausea, headache, dizziness, and depression. In extreme cases unconsciousness. Move the affected person to fresh air. If not breathing, apply artificial respiration. SEEK MEDICAL HELP URGENTLY.

Contact with Skin and Eyes In the course of their work some people continually handle petroleum products. The hands can pass these products on to other parts of the body. If this occurs regularly and frequently it may give rise to various skin complaints. Prolonged contact through improper use can cause dermatitis or even, where heavy contamination occurs, over many years, possibly skin cancer.

Thank you for comments but I

Thank you for comments but I think some of them are inaccurate.

I am not aware of where you have obtained your information. The Shell material safety data sheet (MSDS) on diesel states:


And as for causing cancer:


In other words the rats had to be fed large quantities of diesel to induce cancer.

Kerosene, which is a recommended solvent for use with NO Borer fluid should only be used in areas of good ventilation and good personal protection equipment worn. Kiwicare also recommends painting on the product or using a coarse spray rather than a mist.

The Shell MSDS for kerosene states:

Inhalation: In applications where vapours (caused by high temperature) or mists(caused by mixing or spraying) are created, breathing may cause a mild burning sensation in the nose, throat and lungs.

Kiwicare does not recommend the use of diesel with NO Borer Concentrate. The recommended solvents for good product penetrating are turps and kerosene.

Are you or your company

Are you or your company listed on the Pest Management Association website -



Are you a member of the Pest

Are you a member of the Pest Management Association of NZ?

Hi i am also a Licensed

Hi i am also a Licensed commercial and domestic pest controller (BORER PROOFING SPECIALISTS) We are based in Christchurch and service surrounding areas. If you have any further questions feel free to call me on 03 9814022 i wrote the info on not using kero etc for the reasons given above

Beware of spraying deisel or

Beware of spraying deisel or kero under floor or in roof voids, as the Shell oil company that supplies it states it is not to be sprayed in a confined area with out using an air supply like breathing apparatus as used when doing a gas fumigation. if you do go ahead and spray with out using this you will at the very least get a serious head ache, the down side of this is, that it is from a lack of oxygen to the brain, however you also risk suffocation under the house causing death or brain damage!!! If that has not put you of, Shell also states it -will! cause skin cancer if it gets on your skin ie face from the mist landing on it while spraying. Do Not Use Diesel or Kerosene these are dangerous solvents!!!!!

Hi Richard, If the wooden

Hi Richard,

If the wooden ceilings are of unsealed timber, i.e. not painted, varnished or polished they should be sprayed or painted with NO Borer Concentrate to erradicate the borer and give long term ongoing protection. However, if the timbers are sealed, and you don't fancy the work involved in striping the timbers, then Borafume Fumigators used over a period of 4-5 years will give you good reduction in borer activity, but little ongoing protection. So use Borafume fumigators regularly thereafter to maitain control.

Hi. We have identified borer


We have identified borer in the vaulted wooden ceilings of our cottage. It is a difficult area to access and treat the holes individually. What other options (e.g borer bomb) are available?

Thanks Richard

Use Borafume Fumigators

Use Borafume Fumigators under the house if you are unable to get under to treat the floor timbers with NO Borer Fluid. The wooden furniture will best be treated with aerosol Borer Injector by injecting individual flight holes and by treating any bare wood with borer fluid. The handy ready to use NO Borer is ideal for treating bare wood on pieces of furniture.

Hi there We have borer in

Hi there

We have borer in our floor boards and now attacking some of our wood furniture. Are we best to bomb under the house or inside the house? I am concerned about bombing in the house as have small child.

Thanks for your advice

Hello, There are some


There are some insects other than borer beetle that will us ethe borer flight holes as a place to hide or lay eggs. Although the adult female borer beetle often lays her aggs back in old flight holes it is unlikely that is what you are seeing.

I've noticed small insects

I've noticed small insects with wings hanging around the borer holes (common borer) and going into the holes. Any idea what these would be?

Diesel is a BAD idea. My Dad

Diesel is a BAD idea. My Dad treated a cabinet that had picked up borer while in storage by carefully injecting each borer hole with diesel, using a syringe. It may have killed the borer, but that cabinet, and anything you put in it has reeked of diesel for last 10 YEARS since! It makes keeping glassware or plates or anything to eat or drink from in the cabinet impossible as they pick up the smelll too: so the cabinet is now pretty much useless.

I should also have mentioned

I should also have mentioned that borer like timber that contains a little moisture. That is why they attack floor timbers where the moisture from the ground keeps humidity higher than in the roof. So check that there is good ventilation to timbers and fix any leaks. A dehumidifier and/or air conditioner will help to dry out the interior of a house and reduce borer attack

Permethrin is the active

Permethrin is the active ingredient of most borer treatment products including NO Borer from Kiwicare. Permethrin is a synthetic version of pyrethrum that is extracted from chrysanthemum flowers and has the same mode of action but is designed to remain effective and protective for much longer. Permethrin is toxic to borer but of extremely low toxicity to you or me and that is why it is used in many common household insecticides.

The other treatment used to get rid of borer in infested timber is sodium octaborate. This is also of very low toxicity but it requires the timber to be very well saturated to leave a high level of the chemical on the timber where borer would attack it. It is usually only used by professional operators with the correct equipment.

You can prevent borer attacking timber by using ready treated timber or hard heartwood timbers which borer cannot attack. Also borer do not lay eggs on painted or varnished surfaces. The problem with painted weatherboards is that the borer attack from the unpainted surfaces inside the wall.

I hope that is of help.

is there a non-toxic way to

is there a non-toxic way to get rid of borers?????

Hi Don, These are exit

Hi Don,

These are exit holes. The entrance holes for wood boring insects are so small as to be almost undetectable. The female lays her eggs in or on the wood and the tiny larva that hatches burrows its way in. The risk with the exit/flight holes is that the adult females often choose old flight hole to lay her eggs, giving them protection and bare timber to start feeding on when they hatch. That is why I suggest treating the hole with a NO Borer Injector to kill any egs or larva in there and to prevent adult laying eggs in them.

I hope that helps.


Hi there, that you for the

Hi there,

that you for the reply. Yes, the holes are oval, and 6x4mm and 5x4mm. There has been no further activity, but I'm not sure if these are 'exit' holes or whether the little guy is still in there burrowing away....

many thanks,


Hello Don, If the sideboard

Hello Don,

If the sideboard was fumigated on arriving from China (as it should have been) there should not be any live borer in it at that point. The only way it could have then been attacked was here in New Zealand. This suggests to me that the sideboard has been here for at least two years or it wasn't successfully fumigated. If not successfully fumigated then there is a risk that what has caused the damage is of foreign origin.

The larger flight holes that you describe could be from the native Two Tooth Longhorn borer. Are the flight holes oval rather than circular and as large as 7mm? This native borer can do great damage because the labyrinths they produce are so much larger.

If the flight holes are only a little larger than you are used to with the common borer then it is likely to be the native cousin whose flight holes are around 3mm in diameter.

There is one other possibility. Could it be that the flight holes were already there but not noticed? If so the sawdust known as frass could have fallen out of existing holes when the side board was knocked or moved.

The sideboard can be treated using the NO Borer Aerosol Injector and NO Borer fluid as described below.

I would also suggest letting off NO Borer Borafume fumigators in the house to knock off any adult beetles about and doing a pretty thorough check around other timbers in the home now and over the next several years.

I've noticed two fresh holes

I've noticed two fresh holes in my oak sideboard, and a pile of 'sawdust'. There is no other evidence of any other holes or old borer anywhere in the house. The holes are larger that what I've experienced from borer before, about the size of a large nail hole. The sideboard is about 6 months old, and originated from China. Even though the container was fumigated, is it possible it's a foreign pest? The reason I ask is the size of the hole is quite unusually large to what I've seen before.

Piano Borer Hello. This may

Piano Borer

Hello. This may be a question of how valuable your piano is. If your piano is antique or of high value you may feel is worth contacting a fumigation company. They can seal the piano in a container or plastic and fumigate with methyl bromide. NO Borer Borafume fumigators are not designed to pentrate the timber fully and would not have the same effect, even if the piano was sealed. MBr fumigation is very much a professional operation and should only be undertaken by a registered fumigator. Methyl bromide will penetrate all the wood and kill all insects within it. However, it does not provide any ongoing protection. Check the Yellow Pages for local MBr fumigators.

Carrying out treatment of the piano with NO Borer spray and injector will protect your piano for many years. I appreciate that it may be difficult to reach some parts of the piano where there are flight holes but it may not be necessary to treat all the exposed (i.e. unpolished or unvarnished) surfaces and still get good control. However, be aware that this treatment will not eradicate the borer larvae that are deep in the timber until they emerge.

Ideally a combination of fumigating followed by protective spraying and injecting would be the way to go for full protection.

I hope that is of some help.


I've got borer in my piano,

I've got borer in my piano, what's the best way of treating that? Although the borer is in the wooden frame and casing (rather than in the mechanisms), painting on No Borer concentrate or injecting into borer holes does not seem practical as they are mostly inside or underneath (as well as at the back). There doesn't seem to be any borer anywhere in the rest of the house (which is only 20 years old). One idea I've had is to fumigate it by placing the whole piano inside a giant plastic bag, but I don't know whether that would work and I don't know where to get such a plastic bag from. Grateful for advice.

Hello, The smell of kerosine


The smell of kerosine will usually have gone sooner than 2 weeks but it does depend on the area treated, ventilation and the weather. If you are treating the sub-floor and the floor is well sealed i.e. no gaps up to the house, there is good ventilation and the weather stays warm and dry the smell will disapate in a few days.

The Kiwicare ready to use trigger spray product is water based and so has very little smell but it is only suitable for small areas of timber and does not penetrate into the timber as well as the concentrate in kerosene or turps and therefore will not give protection for as long as the concentrate.

Good luck.

im thinking about treating

im thinking about treating my under floor with kiwicare concertrate and kero just a bit worryied about smell does it go after 2 weeks for sure?

Hi, The new holes can be


The new holes can be identified if you have good eyesight and see that the wood inside the hole is clean. Older holes get dirty over time.

The best times to use Borafume fumigators is during the flight season from November through to March. Ideally twice in the season, say November and January. In order to get the best control borer bombs should be used for at least four years consecutively because the borer larvae (woodworm) eat their way through the timbers for 2-3 years before emerging as adults and the bombs target the adult beetles.

I hope that is of help.

As I live in an old villa in

As I live in an old villa in otago it is hard to determine old holes from new. When should I bomb to get the most from it and how often should I do it. thanks

Checking and treating

Checking and treating timbers inside a wall where there is no access is difficult without opening up the wall. However, if you are seeing flight holes appear on the external wood i.e. the outside of weather boards or the panelling inside the house, then you know that the wall is being attacked by borer. You can also be pretty sure that there are many more (typically 4-5 times as many) flight holes on the wall interior.

Ideally the timber should be treated with NO Borer or similar by removing some weatherboards or interior panelling. If this is not possible or desired the option of injecting the visible flight holes with NO Borer Injector and using fumigant 'bombs' like Borafume can slow borer attack significantly and over a period of 3-4 years use can reduce activity to almost zero.

I have never seen an official figure for the number of old houses in NZ that have a borer infestation. The figure would vary by geographic location and the quality of the building material used. Borer attack the softer sapwood and leave the harder heartwood untouched. My guess after surveying many houses around the country would be that the majority of untreated houses over 50 years old have active borer infestation.

Hi, How could we check and


How could we check and treat timbers inside the wall or where it is impossible for people to reach. is there a figure as for what percentage of old houses would have been borer infested in NZ? Thanks.

Awesome tips here

Awesome tips here

Borer in furniture. Hi

Borer in furniture.

Hi Mike,

Once the NO Borer concentrate and turps have dried off completely the cabinet will be safe to put the baby clothes in. The smell of the turps will be a good indication of how well the treatment of the cabinet has dried off. The smell of the turps on the clothes would be more of an issue than the insecticide in the NO Borer.

Kiwicare Borer Advice