Entomology (Study of Bugs)/identify debris


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QUESTION: I live in a suburb of Chicago and every year I get ants and put out traps and that usually takes care of them. but after they are gone I get this type of debris in the corner a bathroom. It looks like black pepper and I don't see anything that looks like a body. I have a dog and don't really want to use bug spray. But I do want to get rid of this. I don't know if something is in the wall or what. I don't see anything flying or walking around.ants are gone but I get this stuff for months.

ANSWER: Shell,

This debris is possibly from a carpenter nest(s) in the exterior wall (see http://www.livingwithbugs.com/carpenter_ants.html for info about these ants). If the source of the debris is carpenter ants there will be small holes directly above these areas. The ants kick debris out of the holes as they excavate. Post a follow up if you can locate these holes and we can discuss control options. Don't use bug sprays, they won't work well.

Jack DeAngelis

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QUESTION: Jack, thanks for answering so fast. I know exactly where the two holes that are located on the molding of the window wood trim.....they are man made or should I say woman made by me! this window has a valence on top and had a cafe type curtain on the lower half that I had drilled holes into the woodwork years ago. I no longer use the lower curtain and took off the hardware but never fill the two holes and I would bet that this debris comes out of those holes and ends up in the corner there because it is right above it. okay so now what can I do to stop these critters without using something that is toxic to me or the dog. in years past I have put flea and tick powder at my front door threshold which isjust the other side and obviously ant traps which is in one of the pictures

Carpenter ants should be treated from the outside rather than the inside (see http://www.livingwithbugs.com/carpenter_ants.html for details). The basic idea is to surround the structure with a barrier of insecticide that the ants must cross to forage for food and water. They will bring the insecticide back to the nest(s) as they return. Carpenter ants must forage outside the building (house) for most of the year. The last step is to deploy special baits (follow links in the page cited above) that work in conjunction with the insecticide. This can be a DIY project but some people find it easier to hire a pest control company. There are detailed instructions in the links cited above.

Jack DeAngelis  

Entomology (Study of Bugs)

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Jack DeAngelis


I can answer questions in any area of entomology (study of insects, spiders, mites, ticks, and other terrestrial arthropods). Contact me about home and garden insects, insects that bite and sting, and insects that damage homes such as carpenter ants and termites.


20 years as university extension entomologist, now retired; currently publish a website about home and garden insects.

see www.livingwithbugs.com/resume.html

Ph.D. in Entomology

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