Subject:  Wood borer in finished hardwood floor.
Geographic location of the bug:  Brant County near Grand River & Brantford. ON
Date: 11/18/2017
Time: 10:25 AM EDT
Per attached pictures, grub was located by blowing out fine white sawdust from 3.25″ long bore hole and injecting wasp an hornet foam insecticide into the hole to the depth of the hole. The grub moved to the entrance and was removed. The hole was discovered when the surface of the floor sank and in probing the very thin wood and varnish were lost. Further slivers were raised in probing the hole. Can you identify the species?
How you want your letter signed:  Gord Burkholder

Round-Headed Borer

Dear Gord,
Unfortunately, the image of the Round-Headed Borer is considerably less well focused than the image of the wood damage, but even if the image was better quality, we would most likely not be able to provide more than a family identification.  Round-Headed Borers are the larvae of Longicorn Beetles in the family Cerambycidae, and knowing the host plant might be helpful.  What we can tell you is that the larva was most likely already in the wood when the tree was cut, though sometimes the beetles will lay eggs in freshly cut logs.  We can state with relative certainty that the larva was already in the wood by the time the lumber was milled.  Longicorns do not infest milled lumber, so you do not need to worry about further damage, unless there were other larvae in the wood prior to milling.  Do you know the type of hardwood and the location where the trees were grown?  That might help with a more definite identification.  We have heard of incidents when adult beetles will emerge from lumber milled many years in the past.  You might find interesting information on the article entitled “Identification of wood-boring beetles (Cermabycidae and Buprestidae) intercepted in trade-associated solid wood packaging material suing DNA barcoding and morphology” where it states:  “Global trade has created a pathway by which nonnative species may cross once impervious natural borders such as oceans and mountains.”  That site acknowledges “The larvae depicted are visually similar and are difficult to identify below the family level. “

Wood Damage

Thank you Daniel;
I should have added more info. The floor has been down almost 8 years and the oak came from Quebec. There have been no other indications of other infestation. Part of the house heating is done by a wood stove and I have some concern that the species may have been introduced from the firewood.
Gord Burkholder
Hi again Gord,
We are relatively confident this individual was in the wood at the time of milling and not introduced from firewood.
Location: Brant County, Ontario, Canada

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