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Pest Control/powderpost beetles in new bamboo floor


bamboo floor01
bamboo floor01  
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bamboo floor02  
I live in Philadelphia, PA. Two and a half years ago I bought a 100 yr old row-house that has been remodeled in 2011. During the inspection we found on the brand new bamboo floor some tiny hole, on the second floor and my realtor stated it was just some nail hole. This guy is a reliable person and seemed pretty sure about it. Some month after the closing the problem spread out to both floors, just along the perimeter of the house though. The inspector minimized the problem, saying it wasn't a re-infesting species of insect and the damage was just localized to those boards. After asking two pest controllers, I was told to wait to see if further holes would have emerged and nothing happened with the floor since then. Now I've noticed new smaller holes on the main stair raisers, though not sure they've been there since the beginning. The bamboo floor was purchased at a local HD store, and put on the existing wood underlayment (the contractor kept the old woodfloor sublayer, visible into the basement ceiling). I read all posts about powderpost beetles and checked for evidence of insects or powder but couldn't see anything. What are my options now? I'm thinking at replacing the whole bamboo floor through my home insurance and treat the joists and wood wherever possible with some insecticide. I also read about heat treatment and fumigation, however due to the high costs I'd rather consider these options as final resort. Any help would be much appreciated. Many Thanks

ANSWER: Giuseppe,

I think these are old (inactive) emergence holes or possibly not emergence holes at all (see for info about identifying these beetles). The holes are not round which is characteristic for an active emergence hole. This plus the fact that you've not found the "powder" indicates that these are not active emergence holes of powderpost beetles. Some of them do look like nail holes.

Jack DeAngelis

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QUESTION: Jack, many thanks for your quick reply.
I read the articles you suggested. Very useful, thanks.
But how do you explain the fact that these holes have appeared right after the installation? And just along the perimeter walls of the house? Two of the boards however, were in the middle of a room on the second floor. I also noticed some small insect flying into the basement, the size of a fruit fly or smaller. Might it be some powderpost beetle?
The holes on the stair are much smaller and look rounded. I will post a photo of these latest ones tonight.

ANSWER: OK, I'll wait for the new images. It is often difficult to tell if holes actually just formed or if you just noticing holes for the first time. The presence of the powder is really the best way to distinguish old from new.

Jack DeAngelis

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QUESTION: Here are photos of the holes affecting the raisers of the stair.
Most of the steps are affected, with some smaller and others bigger.

The holes are too uneven (ragged) to be emergence holes plus I think I can see paint inside the edge at least one of them. The paint indicates that the hole was there before the surface was painted. Again, I'd guess that these are not recent emergence holes from powderpost beetles.

Jack DeAngelis

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Jack DeAngelis


I can answer questions about the control of pest insects, spiders, mites and related arthropods. These household pests include termites, carpenter ants, powderpost beetles, nuisance ants, bed bugs, cockroaches, fleas, wasps, and many others. I can also answer questions about using pesticides and other pest control tools such as baits and traps.


I am a retired university extension entomologist. I've taught and conducted research in urban and agricultural entomology. I've published over 70 extension publications, 20 research publications and several books about insects.

Ph.D. in Entomology

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