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.
Ambrosia or Pinhole Borer BeetleThe 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 australisPhotographer: Kate Sparks, Source: Museum Victoria
Dampwood BorerThe 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 australiensisPhotographer: Kate Sparks, Source: Museum Victoria
Wood damage by Dampwood BorerPhotographer: Kate Sparks, Source: Museum Victoria
Longicorn beetlesThese 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. Photographer: Kate Sparks, Source: Museum Victoria
Powder Post BeetleThis 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 BeetlePhotographer: Kate Sparks, Source: Museum Victoria
Particoloured Auger BeetleThe 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.
The Particoloured Auger Beetle, Mesoxylion collarisPhotographer: Kate Sparks, Source: Museum Victoria
Wood-boring WeevilThis 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 rhyncoliformisPhotographer: Kate Sparks, Source: Museum Victoria
‘Honeycomb’ damage cause by larvae of the Wood-boring WeevilPhotographer: Kate Sparks, Source: Museum Victoria
Furniture BeetleThe 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 punctatumPhotographer: Kate Sparks, Source: Museum Victoria
‘Honeycomb’ damage caused by larvae of the Furniture BeetlePhotographer: Kate Sparks, Source: Museum Victoria
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.
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.
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.
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?
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.
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.
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 email@example.com
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!
Hi Adam, if you can collect any beetles from the timber we are happy to have a look at them and try and confirm the identity for you.
At the museum we use freezing almost exclusively, but we have the advantage of a walk in minus 20 degrees freezer. Depending on the size of the object you could try freezing it. Another option would be to heat treat the wood by placing the object in black plastic and placing it in the sun (obviously this works best in summer). The Department of Agriculture site 'Approved treatments for timber and wooden related products' is a good resource. This also has links to people who can undertake treatment, although this may be more in the context of people undertaking industrial scale treatment.
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