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powder post beetle damage © Daniel Friedman at InspectApedia.com Evaluate & Prevent Powder Post Beetles & Old House Borer Structural Damage
+ treatment of wood furniture for powder post beetles

  • POST a QUESTION or COMMENT about powder post beetle damage at buildings: how to recognize & assess powder post damage to wood structures

Guide to powder post beetles & old house borers in buildings.

This article provides powder post beetle & old house borer insect & rot damage photographs, inspection advice, and lists additional articles that discuss the inspection, detection, prevention, and repair of structural damage from insects (termites, carpenter ants, carpenter bees, powder post beetles, and other wood destroying insects), indoor mold, rot and building leaks or water entry.

Our page top photo shows our client holding a screwdriver that penetrated a powder-post-beetle-damaged beam fully to the hilt of the tool - indicating severe structural damage to a beam damaged by powder post beetles.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Powder Post Beetles - Old House Borer Damage Photographs

Powder post beetle old house borere damage photographs (C) D Friedman D Grudzinski ... Powder post beetle old house borere damage photographs (C) D Friedman D Grudzinski

In our powder post beetle photos above, while there was significant beam damage, the infestation did not appear active.

Powder post beetle damaged wood will show multiple tiny holes, about 1/8" in diameter, leaving the outermost surface of the wood otherwise intact. Attacks on wood structures or furniture by this insect are notoriously difficult to treat and they've been the subject of worldwide study for more than 100 years (Hopkins 1903), with growing attention following the second World War.

Since the year 2000 L. brunneus is gradually being replaced by L. cavicollis. Other species of the subfamily Lyctinae are rarely found.

In the past L. brunneus was a typical indoor pest in Central Europe which was brought into new buildings with infested wooden materials or furniture.  ( Pospischil 2017)

Probing you will find powdery sawdust and damaged wood just below this skin. The older the powder post beetle (or old house borer beetle) damage is, the deeper into the wood the damage will extend.

For this reason, strategic probing is important to assess the depth of damage to the wood and thus to the wood structure. When powder post beetles are active you may see light dusting of fine wood powder around some of these holes as well as on surfaces below.

We look for the presence of fine wood powder around the insect exit holes or on the ground below the damaged infected member as indications of recent insect activity.

Below we are probing to determine the depth of insect damage into the beam;

Powder post beetle old house borere damage photographs © D Friedman at InspectApedia.com

and in the next photo below you can see powder post beetle damage in a hand hewn beam.

With the absence of fresh fine sawdust powder around the exit holes in these beams one might infer that the insects were not active at the time of inspection.

Powder post beetle damage to hand hewn beam © Daniel Friedman at InspectApedia.com

Below: a sketch of a powder post beetle larva (Snyder 1938) cited below in this article.

Powder post beetle larva details - Snyder 1938, cited & discussed at InspectApedia.com

Below are more photographs of old house borer or powder post beetle damage in a floor support beam. We probe the structural member to find the depth of insect damage as a step in deciding if structural repair, reinforcement, or replacement are needed.

How to assess the extent of structural damage from powder post beetles

Details about when, where, how & why to probe wood structural and nonstructural components on buildings are found

at STRUCTURAL DAMAGE PROBING.

Assessing the extent of structural damage to wood framing members in a conventional building inspection involves the following phases and procedures:

Examples of probing powder post beetle infested wood for structural damage

powder post beetle damage © Daniel Friedman at InspectApedia.com

Shown below, the ground-off ice pick wood probe s finding less-severe damage than the "to the hilt" stab of my dad's screwdriver demonstrated by our client above.

Powder post beetle old house borere damage photographs (C) D Friedman D Grudzinski

Watch out: while we advise against unwarranted cosmetic damage at a building interior, strategic probing of wood sills, rim joists, or floor structures (or other wood members) can disclose severe structural damage that was otherwise not evident.

Below, even our pen was able to easily puncture this termite-damaged joist that had been "cosmetically-repaired" using wood putty

Powder post beetle old house borere damage photographs (C) D Friedman D Grudzinski

Old House Borer Beetle risk from firewood?

Reader question: old house borers, adult beetles & larvae found in firewood stored in garage

Adult old house borer beetle Hylotrupes bajulus (C) InspectApedia DD

We recently discovered the emergence of hundreds of, what looks like, Old House Borers from firewood that was stacked in our garage.

We've taken the firewood out of the garage now (where we could hear the larvae feeding) but are wondering if there's a possibility that they've infected the house as we have seen dozens crawling around the garage and have found a couple of adult/baby ones in other rooms of the house.

I've attached a picture of the beetle. Any feedback would be very greatly appreciated. - D.D. 6/4/2014

Reply:

Indeed the beetle in your photo looks like an adult old house borer beetle (Hylotrupes bajulus) -

Close up photo of old house borer beetle exit holes & wood damage © Daniel Friedman at InspectApedia.com

Removing the infected firewood was a smart move. I would not be too nervous about seeing a few beetles or larvae that needed to be cleaned up on a garage floor.

IF the firewood were stored for many months against wood framing, indeed that framing could become infected too - you'd expect to see the small borer openings such as those we show in the article above.

If you see such infection (which is unlikely given the history you cite) send me some photos and I can comment further and of course a local pest control operator can apply a topical pesticide.

At above left I include a close-up photo of old house borer beetle exit holes - these are typically around 1/16"+ in diameter.

If the home has an accessible basement or crawl area that's the place to start inspecting with care.

Treatments for Powder Post Beetles & Old House Borers

Powder post beetle old house borere damage photographs (C) D Friedman D GrudzinskiPowder post beetle damage is typically treated with a topical insecticide spray.

Where infestation is severe and active, a tenting and fumgiation procedure (typically using Vikane) can be effective at killing both adult and larval powder post beetles. More on powder post beetle treatment by fumigation is below on this page.

Watch out: it's often the case that this insect pest can appear dormant for a very long time, years, but activity may renew when conditions such as moisture level or temperature change.

Some pest control operators (PCOs) also spray paint the wood surfaces in order to make it easier to spot a renewal of insect activity in the future.

An anonymous reader posted a claim that powder post beetles can be treated by microwave - the comment was deleted as it was basically an advertisement.

However experiments with microwave treatments for powder post beetles have indeed been conducted: wood is heated to 50C (or higher) for 30 minutes.

Watch out: the effectiveness of this treatment varies depending on wood species, moisture content, and other variables, and it may not be cost feasible for some structures or where invasion is extensive. The research is focused on lab and production line treatment of wood, not in-situ treatment in buildings. Excerpting from Fleming et als

Wood temperatures greater than 62°C are lethal to pinewood nematodes and cerambycid larvae infesting red pine in a chamber in which the wood samples remain stationary.

Our preliminary findings also suggest, however, that nematodes or larvae in lumber in which the mw field is continuously moving, either by rotation or on a conveyor belt, die at lower wood temperatures than in a batch system without movement.

We recommend that additional experiments with non-stationary, commercial equipment be conducted to investigate this phenomenon further.

Additional assessment of the effects of conventionally heated vs non-heated mw chambers on lethal mw doses would also be helpful for the commercialization and regulatory process.

We can conclude from our experiments that commercial mw treatment (2.45 GHz) of 1-inch thick red pine lumber infested with cerambycids or pinewood nematodes is a feasible alternative to conventional heat treatment or methyl bromide fumigation. - Fleming (2005)

Question: Powder post beetle (Lyctoxylon dentatum) infesting a Siberian elm desk: 12 Treatment Options

Power post beetle damage to furniture: identification, treatment, prevention (C) InspectApedia.com Kiersten

2021/03/30 - Kiersten
I have a desk made of pine and Siberian elm with some wood borer infestation. The bugs/beetles are small, brown, narrow and seem to have several legs on both sides.

Attached is a picture of the damage just under the surface of the elm that came away.
I would appreciate any help. I have not (as of yet) kept one to take a photo of.
Thank you.

Moderator reply:

@Kiersten, sorry but from just your photo I cannot identify the word damaging insect. If you see what looks like mud or mud tubes that you probably have termites. Of course it could be something else. Try taking one of your insect to your local farm at home or environmental center. Or post a photo here for identification.

It's unusual to see surface damage and exposed insect galleries in the summer wood of the furniture like that in your photo. Usually all that we see of powder post beetles damage or a small holes in the surface of the wood.

It'd be useful to see a sharp photo of your powder post beetle as they're usually pretty shy about having their picture taken.

Reader follow-up:

I found one and it's a powder post beetle.

Powder post beetle identication photos Lyctoxylon dentatum (C) InspectApedia.com Kiersten

Moderator Reply: treatment & prevention of powder post beetle damage to wood furniture

In a less-common case I studied in Newburgh, New York decades ago, in a home that was virtually entirely eaten and destroyed by termites we found termite infestion in the legs of tables and chairs that had not been moved in years; termites entered the furniture by tunneling up through a wood floor into the furniture legs.

But in furniture that is more-often moved about, I suspect that at least sometimes the insect damage such as your powder post beetle infestation of a wooden desk is caused by larvae or eggs that were present in the wood at the time that the furniture was actually constructed.

Powder post beetles are difficult to treat effectively as their larvae can be deep inside the wood where they may survive for more than a decade (Lippert 1994).

Are Your Powder Post Beetles Active?

Old powder post beetle damage manifest when wood is sheared into plys to construct plywood (Snyder 1938) at InspectApedia.com

Above: tunnels of old powder post beetle activity in lumber that was sliced into plies in the constrution of plywood. (Snyder 1938).

Building owners/occupants can spot new powder post beetle activity by noticing very fine fresh light-yellow or pale yellow coloured sawdust around the small exit holes in wood. Other experts describe active powder post beetle frass as "light and fluffy" or as a "flour-liek powder" found on or piled beneath the infested wood. (Snyder 1938)

Old beetle frass will be darker in coluring, often a brassy colour or even brown, and it is usually more-adhered to the wood surface, having bonded, perhaps, by cycles of moisture or even by a prior pesticide application.

Twelve Beetle-damaged furniture treatment options

Below: powder post beetle larvae may be deep within wood where they're not much bothered by surface-applied pesticides. (Snyder 1938)

Powder post beetle larvae in wood (Snyder 1938) at InspectApedia.com

In buildings pest control workers often apply a topical pesticide at intervals;

But for treating beetle-infected furniture some different measures may be more successful.

Watch out: before choosing any wood-destroying insect control chemical be sure to review the safe-use procedures necessary; some pesticides are dangerous and can only be applied by a licensed professional.

At REFERENCES FOR CONTROL OF POWDER POST BEETLES / WOOD BORERS you'll find research artilces and more details about these methods for treating powder post beetles in furniture (as well as in wood structures).

  1. Dry out vulnerable or beetle-infected wood:

    keeping moisture levels in wood framing or furniture below 18% helps wood resist attack from powder post beetles, termites, carpenter ants, and various fungi or molds.

    Really? Well yes, but drying out wood, while it may retard powder post beetle development, won't reliably kill off insects that have already infested the wood. Because eggs can sometimes survive for more than a decade, should conditions become more moist in the future, powder post beetle activity may well resume.

    To pursue this strategy see

    BASEMENT WATERPROOFING
    and
    CRAWL SPACE DRYOUT
  2. Freezing to kill powder post or furniture beetles:

    if your powder post beetle or furniture beetle-infested furniture is located in a cold climate such as northern Minnesota, you may be able to kill the insects entirely if you can keep the furniture very cold (10° - 15°F for 72 hours or longer). As recently we were living in -24°F in Two Harbors for several months, when weather is dry and that cold, such treatment is entirely plausible.

    A few cycles of freezing, warming, and re-freezing can increase the effectiveness of this approach. (Lippert 1994).
  3. Fumigation to kill furniture beetles:

    fumigation (in most cases, by licensed PCO only) in an enclosed chamber or plastic is an option for furniture, and has also been used for entire buildings by "tenting" the building.

    Where it can be applied safely, fumigation can effectively kill insects even deeper into the wood than can surface sprays or coatings, but keep in mind that fumigation provides no residual protection against re-infection. (Jones 2008)

    Watch out: some chemicals such as methyl bromide discussed in older powder post beetle control articles are now considered unsafe and should not be used.

    See details about using sulfuril fluoride (Vikane)

    at POWDER POST BEETLE FUMIGATION TREATMENT
  4. Gamma radiation of furniture:

    Though this method had been found effective (Zahran 2016) it does not have practical application for household furniture except possibly in treatment of valuable, historic artifacts (OPINION of the editor).
  5. Heat to kill powder post beetles

    was described by Snyder (1923) and of course others; for small items, treatment by microwave may also work.
  6. Immersion in pesticide to kill powder post beetles:

    may be feasible for small wood items that can be immersed in a borate solution. (AmOR-S®, Boracane®, Safbor®, TIM-BOR®, or equivalent)
  7. Plant extract treatments kill powder post beetle:

    using lemon grass and lantana plants has been reported somewhat successful and may bode well for safe treatments of powder post beetles. (Batt 2013)
  8. Presure injection of pesticides:

    into wood using wicks inserted into the bore-holes left by beetles (in most cases, by licensed PCO only)
  9. Removal of the infested wood:

    is an option in cases of building structural repair and may also be an option for some furniture.
  10. Steaming

    of infected wood has been tested and found not effective against the Aobium sp. powder post beetle in bamboo (Febrianto (2013) though it was more-effective against some termite species.
  11. Surface or topical application of pesticides:

    using a spray or brush-applied pesticide (in most cases, by licensed PCO only) is a very common treatment method in houses such as where active powder post beetle infestation is found in wood beams or joists over a basement or crrawl area; for furniture borates can also be applied as a brushed-on slurry or even a thicker paste.

    Our OPIION is that surface treatments for wood damaging insects that are often deep within the wood is slow and incomplete in effect. Also in our experience surface treatments of insect-infected wood are limited in penetration and thus effectieness.

    Copper-based pesticides penetrate only the first 1/8" or so of wood, depending on wood species and porosity.

    Surface coating of insect infected wood with a boron-based insecticide will be ineffective if the wood is furniture whose surfaces are already sealed by paint or varnish.
  12. Seal the surface of furniture:

    where you think treatment has been successful, or where wood furniture is not already infested by powder post or furniture beetles, seal all surfaces with a varnish or lacquer. This will reduce the chances of a future infestation from outside the furniture itself.

    I [DF] have applied this strategy in the application of clear sealants to the otherwise un-coated wood surfaces of furniture such as the interior and under-side of desks and bureaus and their drawers or pull-outs. I use a spray shellac for a clear, fast-drying method of coating irregular surfaces, applied outdoors in good weather, and with the application of two or three coats.

    In homes where powder post beetles have already infected wooden beams, joists, posts, and where those have been treated, some owners paint a sealant on the framing both as a preventative measure and also because that coating makes it easy to spot new, fresh frass indicating a new cycle of insect activity.

    Also see our notes about probing wood to determine the extent of damage, discussed above on this page.

    Watch out: however experts warn that if there are already eggs, pupa, or adult insects in the furniture, surface sealants won't stop their future emergence and damage.

Reader follow-up:

I am thinking about calling a pest control control company to treat the wood and keep it wrapped in plastic for a couple of months outside after I sand off the varnish.

The desk top is more than 2 inches thick in places.

I live in Colorado. 2021/04/04

Moderator Reply: Fumigation Treatment of Powder Post Beetle-Infested Furniture

I would be cautious about leaving Furniture outside if it's in a climate that could be humid or wet. If it's so cold where you are that you could freeze at that would be an effective treatment but you wouldn't need more than a few days.

Currently weather in Colorado is mostly well above freezing - so that option's not going to help you before next year.

You could enclose and fumigate the furniture and let it cure under fumigation, but I expect your PCO expert to say that a few days is enough - you don't need months.

A common structural fumigant - applied by a licensed PCO - is Vikane or equivalent. But your PCO may have other suggestions when it's just a bit of furniture being treated for powder post beetles.

Before trying a local wrap-and-fumigate treatment for your powder post beetles, ask your pest control company if they have a local fumigation chamber in which they can treat your table. That would probably be a better, safer, more-effective option and it'll avoid the risk of leaving furniture un-attended outdoors.

Finally: compare the cost of treatment with the value of the furniture being treated.

See this

 

References for Control of Powder Post Beetles / Wood Borers

Research on treating powder post beetle (Lyctid Beetle) or furniture beetle (Anobid Beetle) infestation in wood furniture and in structures and insecticides and application instructions from agencies such as the US EPA are listed here.

Also for another identification photo, below the image of a powder post beetle (Lyctoxylon dentatum) is courtesy of Wikipedia.

Powder post beetle identication photos Lyctoxylon dentatum (C) InspectApedia.com Kiersten

Lyctoderma-coomani-Sittichaya (2009) from an illustrated key to identification of powder post beetle - cited & discussed at InspectApedia.com

Above: Dorsal view of Lyctoderma coomani Lesne, 1932 ecerpted from Sittichaya (2009 p. 40) cited just below.

Powder post beetle pupae, full grown, . africanus (Zahran 2016) cited & discussed at InspectApedia.com

Above: Photomicrograph of ventral surface of full grown pupae of L. africanus (Zahran 2016).

 




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Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Question: Lyctid powder post beetle infesting a blue-pine home-made wooden bed

Powder post beetle exiting infested wood (C) InspectApedia.com Crystal Grant2020/03/06 crystalgrant39 said:

I made a bed out of blue pine sanded and varathane the wood. It has been in the home about two months.

In the last month beetles have come out of the wood. I estimate we have found abut 15 beetles in 1 month.

Do I have to get rid of the bed? Will the beetles eat my house? I appreciate your thoughts. I tried to include a picture of 1 of the beetles.

Reply:

Crystal:

Your photo is of a Lyctid powder post beetle - good going. If you can take a sharper image I'd sure like to include it in the article above.

About your bed:
It sure sounds as if that pine is infested.

It is very hard to completely kill all of the powderpost beetle larvae and beetles in infected wood. That's why standard advice is to "remove all of the infested wood completely"

But let's not give up right away.

You might be able to salvage it by aggressive insecticide treatment.

To do this effectively you'll need to strip all of the wood surfaces of any paint or varnish or sealer (otherwise the insecticide isn't effective). Experts point out that surface treatment ONLY kills the adult beetles as they emerge, it doesn't kill the larvae deep in the wood. (That's why treating powder post beetles is so difficult).

More help and advice and treatment and prevention suggestions for wood destroying beetles is are given above on this page.

I would remove the bedding, dis-assemble the bed as far as possible, then take it outside or out of the living area (such as into a garage) where it can be treated with insecticide and left in sealed plastic covering or bags for a month or two.

Or alternatively, if it is possibe for you to heat the wood without damaging it, (less than 2" thick) to a sufficient temperature (wood internal temperature must reach 140-150 F for 2-4 hours) you may be able to kill the larvae.

Wipe the wood clean, treat it, bag it, wait, then inspect it for sawdust or other indications of insect activity.

Keep me posted.


...

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