Help Identifying Insect

[lbugged]

Entomology is a subject I know nothing about, so I'd appreciate help from you knowledgeable people in identifying what I believe is evidence of some type of insect that makes periodic appearances in my home.

Several times over the past year in my bathroom sink and surrounding countertop I noticed several dozen dark brown specks, about the size of a sesame seed. They seem to grow visibly larger over time (hours). They are quite hard (almost rock like), and apparently quite dense, because they don't easily wash down the sink. When they appear, they seem to be increasing in numbers rapidly over several hours.

I discovered that they emanate from the wall above the sink, at about 6 or 7 feet above the floor (this is a single story house and the attic would be just above). They are inside a small hole in the wall and coming out of that hole - I don't know if the hole goes all the way through the wallboard to the other side or just part of the way through. Each time I've found one of these holes, I've cleaned it up and then patched it. That seems to stop the appearance of the brown specks.

The last time this occurred (a couple of days ago), the weather suddenly changed and the temperature jumped up maybe 20 degrees above its prior high to around 90 degrees. I'm located in California, in the San Francisco Bay Area.

I've attached a photo of the hole in the wall from which the brown specks emanate.

As I was cleaning the hole in the wall a couple of days ago, I thought I noticed a small flying insect near the hole, but I don't know if it is related or not.

If you have any questions I'll do my best to answer. I'm not even sure this occurrence is in the entomology realm, but if you think I should consider other possibilities I'd appreciate your input. Thanks very much for your help.

LBugged

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[lbugged]

Here is a photo of the brown specks as they appear in the sink. Thanks.

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[lbugged]

Here's a close up of the hole in the wall with the brown specks inside. Thanks.

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[Adam Cotton]

Is the wall behind made of wood? It's probably woodworm, a beetle that lives in wood and eats its way through it. The brown specks you see are its frass. The adults make a hole when they want to get out.

If it is a wooden wall, you really need to remove the piece(s) of wood that these beetles are living in, as they will eventually (over a long time) eat a lot of the wood and maybe weaken the structure.

Adam.

[lbugged]

Thank you very much for your reply and helpful information. The house structure is wood frame, concrete foundation, and stucco exterior. So the woodworm are eating the wood frame? Is the best solution to remove the infested wood, or are there other options? Thanks again.

[Adam Cotton]

Contact a local pest control company and they can give good advice based on what exactly they believe is the problem. It may well be possible to treat the wall with an insecticide without having to remove any of the wood. Without treatment or some action the problem is likely to continue/get worse or at least be an occasional problem.

Adam.

Adam.

[lbugged]

Thank you for the help, Adam.