Wood borers you should know

Introduction

The discovery of small, fresh, conical piles of sawdust in your home can provoke one of those ‘sick in the stomach’ feelings. Wood borers!

All borers will do some kind of damage to timber, but all is not lost – there are ‘good borers’ and ‘bad borers’. You need to be aware of the differences between the two groups, because ‘good borer’ damage will be cheap to repair, but it may be expensive to repair the damage done by ‘bad borers’.

The ‘good borers’ are beetles whose damage is limited to the first five years after the timber was milled. They attack mainly soft wood or moist decaying timber, and the damage done to the wood is superficial; it can be fixed by filling with putty and a quick repaint.

The ‘bad borers’ are beetles that can attack hardwood or softwood of any age. The damage is often structural, requiring complete replacement of the timbers, which are often floor boards or major support beams.

GOOD BORERS

Ambrosia or Pinhole Borer Beetle
The Ambrosia or Pinhole Borer, Platypus australis, belongs to the Curculionidae family and has a biology that differs from most other wood borers. In other wood-boring beetles, it is the larvae (grubs) that bore through the wood and create the galleries. In the case of the Ambrosia Beetle, the adult female bores into the timber, creating a central tunnel with side branches. The larvae do not feed on the wood; they eat the fungus that grows on the moist timber gallery excavated by the adult female. The fungus causes a staining of the wood, which is characteristic of Ambrosia Beetle attack. Since the fungus the larva feeds on requires a moist environment, attack is confined to living or recently felled timber. Damage is only superficial.

The Ambrosia or Pinhole Borer Beetle, Platypus australis

The Ambrosia or Pinhole Borer Beetle, Platypus australis
Photographer: Kate Sparks, Source: Museum Victoria

Dampwood Borer
The Dampwood Borer, Hadrobregmus australiensis, belongs to the Anobiidae group of borers. It is a comparatively large beetle that attacks both softwoods and hardwoods, but only wood that is moist or decayed by wood-rotting fungi. As such, the wood affected by the borer is already damaged and therefore the borer is not considered to initiate damage. Typically in a household situation, damp-affected wood occurs in the subfloor parts of the building. Once the decayed wood has been removed and the reason for the damp condition is fixed, no further Dampwood Borer damage will occur.

The Dampwood Borer, Hadrobregmus australiensis

The Dampwood Borer, Hadrobregmus australiensis
Photographer: Kate Sparks, Source: Museum Victoria

Wood damage by Dampwood Borer

Wood damage by Dampwood Borer
Photographer: Kate Sparks, Source: Museum Victoria

Longicorn beetles
These are the cerambycid or longicorn beetles, so named because of their long antennae. Most species attack living trees. The boring is done by the larva (beetle grub), which may take 1–3 years to complete its development. Sometimes, the live tree that was originally attacked may have become part of a house or made into furniture, and the owner can get quite a surprise when a large beetle emerges. Damage is only superficial.

A longicorn beetle, Phoracantha sp.

A longicorn beetle, Phoracantha sp.
Photographer: Kate Sparks, Source: Museum Victoria

Powder Post Beetle
This lyctid borer attacks the sapwood of susceptible hardwoods, but not softwoods. The female lays her eggs in the exposed end-pores of freshly cut wood, or in a living tree that has been damaged. Borer attack is confined to about the first five years following felling of the logs, or when the timber moisture drops below 20%. The larvae feed along the grain of the wood and never attack the heartwood, so the damage is superficial.

Exit holes of the Powderpost Beetle

Exit holes of the Powderpost Beetle
Photographer: Kate Sparks, Source: Museum Victoria

Particoloured Auger Beetle
The auger beetles are bostrichid borers. They attack only recently felled logs and green timber, and only the sapwood of hardwood and softwood is susceptible to attack. The larvae feed along the grain of the wood, so the damage is superficial. The larvae (beetle grubs) produce a fine powdery frass (insect poo). The Particoloured Auger Beetle, Mesoxylion collaris, is the most frequently encountered species. It often bores its way out through the plasterboard during the first summer after a house has been constructed or renovated.

he Particoloured Auger Beetle, Mesoxylion collaris

The Particoloured Auger Beetle, Mesoxylion collaris
Photographer: Kate Sparks, Source: Museum Victoria

BAD BORERS

Wood-boring Weevil
This beetle, Pentaminus rhyncoliformis, belongs to the Curculionidae or weevil group of beetles. It attacks only softwoods, such as pine skirting boards. However, unlike the larvae of the ‘good borers’, which feed along the grain, the larvae of the Wood-boring Weevil meander throughout the wood, producing a honeycomb of tunnels that destroys the integrity of the timber.

The Wood-boring Weevil, Pentaminus rhyncoliformis

The Wood-boring Weevil, Pentaminus rhyncoliformis
Photographer: Kate Sparks, Source: Museum Victoria

‘Honeycomb’ damage cause by larvae of the Wood-boring Weevil

‘Honeycomb’ damage cause by larvae of the Wood-boring Weevil
Photographer: Kate Sparks, Source: Museum Victoria

Furniture Beetle
The beetle, Anobium punctatum, is an anobiid borer and can cause serious structural damage to timber. Attack occurs mainly in softwoods used in areas such as flooring, panelling and furniture. Unlike the ‘good borers’, this beetle can attack old dry wood. The female lays eggs in cracks and crevices or abraded areas in the timber, and the larval period may take several years. The reason it can cause serious damage is that the larvae feed in a meandering manner, producing a honeycomb of tunnels through the wood and destroying the structural integrity of the timber.


The Furniture Beetle, Anobium punctatum
Photographer: Kate Sparks, Source: Museum Victoria

‘Honeycomb’ damage caused by larvae of the Furniture Beetle

‘Honeycomb’ damage caused by larvae of the Furniture Beetle
Photographer: Kate Sparks, Source: Museum Victoria

Further Reading

Creffield, J. 1996. Wood-destroying Insects – Wood Borers and Termites. CSIRO: Melbourne.

Gerozsis, J. and Hadlington, P. 2001. Urban Pest Management in Australia. University of New South Wales Press: Sydney.

Comments (49)

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Matt Carter 21 April, 2009 17:00
I am a winemaker and have a problem with borers eating into my oak barrels, empty or full. I think I have captured one. What can I do to prevent this as the barrels are extremely expensive and worthless with a hole.
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Discovery Centre 24 April, 2009 12:01
Hi Matt, Thank you for your comment regarding your oak barrels. In addition to the suggestion already made that the Museum can try to identify your specimen for you, it may be worth you contacting the Australian Wine Research Institute. This group is dedicated to providing information and assistance to the wine industry. The link below is to their website, best of luck with this. http://www.awri.com.au/
Andrew Cantle 1 April, 2010 12:20
Hi - in the last week I've had around 20 small beetle type creatures take over my kitchen. I think they might be living in the chip board that the kitchen side is made of. But they are difficult to pinpoint. I'm in Sydney. Are there a common beetle type that do this in the area? Happy to send photos in if that helps? Thanks Andrew
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Discovery Centre 1 April, 2010 15:30

Hi Andrew, Museum Victoria offers a free identification service. To send an enquiry, click on the 'Ask the experts' link and then on 'Identifications' in the menu at left. Please provide us with images and, prior to sending us your enquiry, please read our identification guidelines.

Nate 22 April, 2010 17:01
I found what I am quite certain is a Wood-boring Weevil. I live in the Diamond Valley region of the outer northern Melbourne suburbs. I have a lot of fire wood around that is very rotten and also timber building materials. Should I tip the decaying firewood and not wait to burn it, and how worried should I be about the building timber and my weather board house for that matter?
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Discovery Centre 25 April, 2010 14:31

Hi Nate, if you still have the borer it may be a good idea to get it to us and we can then try and identify it for you. Some borers attack only rotting timber, some will only cause cosmetic damage and some can cause structural damage. You can bring the beetle into the Discovery Centre daily between 10 and 4.30, or you can post it to Discovery Centre PO Box 666 Melbourne 3001. Please place the beetle in a small plastic container which won't get crushed in the post with your contact details.

Tim 30 July, 2010 02:10
Please give suggestion as to identity. I cannot send a pic at this time. This beetle is 2 inches long as pupae, 1 1/2"as adult, long antennae, is decimating cherry orchards in Lebanon. I think it is in the Bostichidae family
Discovery Centre 31 July, 2010 12:40

Hi Tim, there are many different species in the family Bostrichidae and without an image we could not attempt to say what species it may be. Museum Victoria does not have expertise on Bostrichid beetles from Lebanon. Is there a Natural History Museum you can contact in Lebanon who may have knowledge of the local fauna?

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Monica 8 August, 2010 10:07
I recently bought four antique bentwood chairs. On the underside they have paper labels from Harnisch & Co and small metal plate labels with the name H. Morris Jones & Co, Chapel St Windsor . They are beautiful old chairs but I have just discovered that two of them appear to have been infested with borers. They have tiny holes and honeycomb-like damage. I did not see any of this damage when I first bought them but I haven't seen any other evidence, such as sawdust-like deposits under the chairs. I am worried that there is more extensive damage to come or that the other two chairs may become infested. Do you have advice on how best to tackle the problem with antique furniture?
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Discovery Centre 12 August, 2010 14:46

Hi Monica, the most important thing is to determine whether the evidence of insects is old and nothing to be concerned about or a current infestation. Obviously if you can find any larvae or adult beetles in the furniture collect them and post them to Discovery Centre PO Box 666 Melbourne 3001 in a small plastic container which won't get crushed in the mail. The CSIRO have also produced a helpful website on wood borer infestation.

Monica 13 August, 2010 11:29
Thank you for that information. I have collected some of what I believe are the borers which have been flying around my apartment. They are very small so I have been unable to identify them. I will try and drop them in to the Museum as I work nearby.
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Discovery Centre 13 August, 2010 12:14

Hi Monica, the Discovery Centre is located on the lower ground level of the Melbourne Museum at the Rathdowne Steet end of the building. We are open daily between 10 am and 4.30 pm. Look forward to receiving your specimens.

Mary 18 August, 2010 13:32
Hi, My house has no cavity in the ceilings as its all timber open beams. As of the last few months I have been finding piles of wood grains on my furniture. There is little hole in various sections and i dont know if i should putty or not as i have no cavity to get a look. How can you identify them if i havent got the insect themselves to show you?
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Discovery Centre 24 August, 2010 15:17

Hi Mary, you could try putting sticky tape over the holes and see if you manage to collect any beetles that maybe emerging that you can then send to us for identification. The other thing you can do is if you can tell us the type of wood you have, if you are aware of any damp issues with the wood, the size of the holes, i.e. 1-2 mm in diameter, 3-4 mm etc and whether they are round or oval in size we may be able to make some suggestions. If you are able to take some good quality photos you could also send those to discoverycentre@museum.vic.gov.au

Jane 1 September, 2010 23:37
Hello, I recently bought a buffet hutch from Ebay... has a lot of holes (roughly between 50 and 100) with black stain around the holes. The holes vary in size but would roughly fit the plastic part of a ball point pen point in them. I treated the hole piece with Rentokil Borer Insecticide by injecting the holes and rubbing over the whole piece roughly. The next morning I found a dead insect on the floor nearby. It looks reddish dark brown and is about 8mm long. I can send photos if necessary. I spoke with a pest control expert as I am extremely worried about this, and he has said that this borer will only affect the piece of furniture concerned and only bores out of the timber once it is an adult and does not do any more damage at that point. If you could give me any further advice it would be greatly appreciated.
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Discovery Centre 3 September, 2010 17:01
Hi Jane, we can certainly identify the insects for you. Simply click on the 'Ask the Experts' link at left, then on 'Identifications'. You'll find a form, as well as identification guidelines, with which you can send us your exact query as well as images.
Kate 4 September, 2013 20:00
Jane, Did the Bora insecticide work? I have them in built in cupboards and have just had my floor boards done when I found them. My floor sander said to avoid removing the cupboards as it will destroy the floor. I am now worried sick that they will spread to my floor boards and skirting boards. My pest controller said they were annoboid bora and they have infested a built in cupboard. A carpenter had told me the cupboards were blackwood but the pest controller was not confident they were. Do the insecticides work and how often do you have to apply them for annaboid bora
Gay Hawkes 17 October, 2010 21:17
Intense infestation of borers in green dogwood I used for frame of a small dwelling.There is much fine dust from holes and these are from 4-7 mm diameter.Nothing seems to work as eradication.
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Paul and Thomas Kruger 9 January, 2011 11:09
Hello Discovery Centre Team, We have just caught a Longicorn beetle (adult, Coptocercus rubripes we think) and were wondering if you could advise us as to what to feed the beetle please ? We assume that the adult will still eat wood but which kind would be best ? Thank you
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Discovery Centre 12 January, 2011 15:08
Hi Paul & Thomas, adult beetles from the family Cerambycidae feed on a variety of substances depending on the species concerned. Many feed on pollen, while others feed on bark or foliage and some can be attracted to sugar baits. You may want to try giving your beetle a mix of flowers, foliage and bark and see if you can find what takes his or her fancy. If it doesn't seem to be feeding it may be good to release it and allow it to find its preferred food source.  
CYNDI REED 30 January, 2011 12:22
Hello, I was dusting my old 1930'radio and a piece of the paint rubbed off to reveal hundreds of teeny tiny orangish eggs?..tiny round things. I grabbed my vacuum and sucked them out, and found another small round hole and took a tooth pick and pressed on it,..more of the lil round things spill oot. I filled the holes with bug killer after vacuuming them out and sprayed all around the floor. Do you know what this is? There are plenty of pictures of the bugs, but not of the eggs. Any help is much appreciated. I'm panicked as I just purchased a 1930's bankers desk!! help! thanks cyndi
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Discovery Centre 15 February, 2011 08:42
Hi Cyndi, it would be really helpful if we could see some of the eggs, so we could put them under the microscope and try to get some idea of what they may be. If you can collect any please feel free to bring them into Discovery Centre on the lower ground level of Melbourne Museum, open daily between 10 and 4.30. This website from the CSIRO will provide you with some good tips for monitoring the presence of wood borers.  
Gulshan 13 February, 2011 03:25
Hi, About October last year (when winter was abt to start) I saw small black insects that resided at all the corners of my house. After a month I started seeing a lot of powder coming out of my shoe rack and had small holes. I chemically treated that and now for 2 / 3 months there is no powder from that. But in past 1 week I saw powder coming of my dining table where a hole of 4 mm was done. There is also powder coming from leg of sofa hole is pin size. Also there is powder coming from wardrobe door where a pin hole is there. Is it possible that wood borer attack spreads from one furniture to another or the beetle(s) has attacked a lot of my furniture. The problem has been visible only since1 week. How can my furniture be protected, also can i protect uninfected furniture. All my furnitures are veneer finished with varnish and malamine spray and interiors are laminated.
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Discovery Centre 17 February, 2011 18:25
Hi Gulshan, it sounds like you are contacting us from the northern hemisphere. It may be best to contact your closest natural history museum to see if they can offer any advice as you may have different borer species to those from our information sheet which is aimed at Australian situations. Best of Luck.
Robyn 20 March, 2011 00:19
I live in Toowoomba in Queensland in a temperate damp climate. I purchased a second hand double bed wooden bed in late January and have today noticed it's riddled with borer damage. Additionally the tongue and groove (possibly pine) walls in my house (built 1930's) where the bed base was stored have some small holes which maybe be borer exit holes and there is a small piece of what appears to be pine attached to hardwood stumps immediately underneath the room (under the house) where the bed base was stored appears to be seriously borer affected. Is it likely the borers were brought into the house via the bed base or is it likely they were here already and completely devoured the bed base in a few weeks?
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tim 6 September, 2011 18:19
hi there, we recently bought a house in donavons s.a. the pine floor is badly damaged by the furniture beetle. when pulled up it is very powdery and honeycombed. it does not appear to have gotten into the hard frame at all. i am thinking about just putting mdf sheeting straight over the top. do they eat mdf?
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Discovery Centre 13 September, 2011 14:12
Hi Tim, we do not believe that furniture beetle will attack MDF.
Tilo Junge 27 September, 2011 20:18
Hello I am a collector of traditional money items. In my collection I have many items made from natural materials. I appear to have a Bird of Paridise plume that is being eaten by something. Is there product I can spray into or around the cabinet, or can place flakes of Napthalene in the draws? Can you suggest anything, should I try and find the critter/eggs? Thanks Tilo
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Josie 24 May, 2012 14:19
Hi; I suspect I have borer in my piano (have noticed some flight holes). When the mature insects fly off out of their flight holes how far can they travel? Could they spread to other furniture in the same room? Or in the same house?
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Discovery Centre 24 May, 2012 16:22
Hi Josie, There are many different species of wood-boring beetles. In order to answer your questions, we would need to know which species of beetle inhabits your piano. Museum Victoria has a free Identification Service. If you manage to locate a specimen, you can either post it to us or drop it off at the Melbourne Museum Discovery Centre. We can then identify it and answer any questions you may have about its biology and behaviour.
Ron Vangorph 22 June, 2012 16:28
Hi A couple of years ago I contacted Ken Walker re Pentaminus rhyncoliformis. He informed me the name had changed to Pentaminus Australis. Not sure if you are aware. http://www.padil.gov.au/viewPestDiagnosticImages.aspx?id=2315 Regards Ron
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Chris 22 October, 2012 22:25
Our home has pine floorboards dating from 1920s and 30s. They have some areas in which possible borer damage has been filled. We have lived here 3 years and have noticed in the last few months that the gloss finish and whatever wood-filler/putty which was between the floorboards and in patched areas is disappearing leaving dark gaps between boards and cracks. Are there any wood damaging insects which are likely to eat the corking/filler? We can't access the underside of the floorboards (first floor with no accessible cavity). Many thanks for any ideas you may have. We live in Sydney.
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Discovery Centre 29 October, 2012 10:25
Hi Chris, we are not aware of any borers or beetles that would consume putty/wood fillers. It may be that general wear and tear has led to the filler drying or cracking and maybe falling out of the gaps; it's very hard to say without seeing it.  
Alberto Montesano 24 November, 2012 20:55
A nice old cherry wood table that has sustained damage by wood borer, the usual 1 to 2 mm holes, after been in a commercial freezer airtight wrap for 10 days at -20 C I would like to fill in the holes and restore the table, however after substantial search I can not find any information on the best process to fill in the small holes. Any information and advice will be very helpful. Thanks,
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Discovery Centre 26 November, 2012 13:39
Hi Alberto, consider contacting the Australian Institute for the Conservation of Cultural Materials for some conservation advice.
kevin bamford 16 February, 2013 22:09
Hi guy's i own a pre-fab railway house (sent out from england 50/60's)i have only now found what i think are borers in baltic pine flooring and hardwood joists would it be any use treating the house now ore would the damage be done thank you Kevin (i have only checked one room because a board started to give way)
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Wroger 18 February, 2013 22:00
Hi I have just noticed that there many holes bored into the brick wall along the side of our house. I asked the builder what caused these, and he said it was the Masonry Bolt "beetle". I would not like to see our beautiful brick wall eaten out by them, what treatments can I apply to the bricks to stop the infestation?
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Discovery Centre 23 February, 2013 13:56
Hi Wroger, I have not heard of the masonry bolt beetle, I have heard of masonry or mortar bees if that is what the person meant? These bees usually burrow into banks of hard soil or sand but where mortar or cement is starting to get weak or is of poor quality the bees can burrow in. The Museum is not involved in pest control but I imagine if you tried to use insecticides you would need to reapply this continually if the bees are attracted to crumbling mortar. If they are presenting a large problem you might want to have the mortar repaired to prevent their access.  
Jenny 17 September, 2013 11:34
Hello, I noticed brown marks on the cornice in one of my rooms and also mud tracks on an outside wall. Immediately I contacted a pest control company and they came out that day (approx a month ago). Good news was that I didn't have termites (the tracks were european wasp related and removed/treated). They couldn't say what was causing the marks but on close inspection showed me they are holes. The roof cavity was dusted and I thought the problem was solved. Just this week, new holes/marks are appearing and are not only confined to the cornice. I have never seen any insects and are wondering if you are aware of what could be eating my plaster? Hoping you can help.
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David 4 October, 2013 23:33
Hi there my house is now 11 years old, I have Sydney blue gum flooring. I have pin holes all over my flooring I have had it checked out twice once 11 years ago and again two years ago and keep being told there was no moisture in the floor and they were no longer active . Though over the years the holes keep increasing . I was originally told the holes were there before the floors got laid and polished, though I have holes through some of the joints doesn't make sense. This has been doing my head in for the past 11 years is there any body you recommend who can come out and give me another opinion, I live in bundoora Victoria thanks
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Discovery Centre 7 October, 2013 11:19
Hi David, ideally if you could get a specimen of what is emerging from the holes you should be able to make some more informed plans on how to deal with them. If there is a particular section of floor boards where you believe new holes are forming place some tape over this area and see if you can catch some of the adult beetles on the tape as they emerge. If you can get some beetles we have an identification service. The CSIRO website also has some tips that might assist on monitoring for termites and borers and also some advice on treatment. 
Chris 9 January, 2014 14:17
I have two big Plywood pieces at my place, recently I am seeing lot of cream color saw dust falling from small pin hole size holes of the plywood.After removing some upper part of the plywood, I observed that the plywood was full with saw dust. Unlike other borers who push the saw dust away from the plywood, this borer is not doing the same. The plywood is packed with sawdust, the ply now looks like "a box filled with sawdust". Can tell me what kind of wood borer is this.
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Discovery Centre 14 January, 2014 11:50
Hi Chris, if you can have a good look in the plywood and the dust that is accumulating and see if you can collect a specimen of what is causing the damage that would be great. Have a look at the CSIRO website which has some general advice on wood borer detection. If you are sure that it is a current and active infestation see if you can find any small beetles which may be present in the timber. If you can collect some feel free to put them in a small container like a pill jar and mail them to Discovery Centre PO Box 666, Melbourne 3001.  
Michelle Walker 2 August, 2014 16:47
Hi My daughter bought an old wooden picture frame which had borer holes in it. I thought it was in active but not sure now as small hole have appeared in some marante wood architraving on floor behind which the frame was leant against. I had soaked the frame with eucalyptus oil before placing it against the floor. Is it possible to have borers attack the wood within 2 weeks? I also found one dead beetle on the carpet behind the frame.
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Discovery Centre 4 August, 2014 12:57
Hi Michelle, the best thing is for us to have a look at the beetle and tell you whether it is a borer or not. If you can place it in a container which won't get crushed like a pill jar and send it to Discovery Centre PO Box 666, Melbourne 3001. Just put a note inside with your contact details and that it is for enquiry number 35260.
andrea simpson 10 August, 2014 12:25
hi im wondering if you can help ive been to plant nurseries, tree specialists but no one can seem to help me, i have 150mt of bottlebrush shrubs that are getting attacked and dying from some sort of borer. they are small white/clear around 3mm in length i have a photo but cant seem to attach to the comment section. any help would be appreciated as im at my wits end .
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Discovery Centre 12 August, 2014 13:12

Hi Andrea

You are welcome to see if our experts can identify the borers via our Ask the Experts page; yon this page you can upload a photograph, but it would need to be a clear image of the animal itself rather than of the damage to the tree. We may be able to identify the animal responsible, but we don't provide control advice, so we may only be able to partly help...but we are happy to try!

sandra 3 November, 2014 13:23
I have been attacked by small black twig looking beetles that barrow into my timber slab breakfast bar they leave little mounds every morning and every now and then I find them dead on the surface of the timber, I have captured a few in a jar but no one knows what they are, I need help to get rid of them any help appreciated
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Discovery Centre 3 November, 2014 16:14
Hi Sandra, the best thing to do is place some of the beetles in a container like a pill jar and mail them to Discovery Centre, PO Box 666, Melbourne 3001. We can then identify them and provide you with as much information as we can. Just enclose a note with your contact details and write down for us the problems they are causing and where they are being found.