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Book Lice

Summary: Book lice populations can build up quickly in stored food products that have been left and forgotten at the back of your pantry shelves. You'll find yourself throwing away a lot of never-used food if you don't use some precautions.

Nathan; BC Canada asks:

I have found tiny bugs in my cupboards so small that they look like dust partials, but they move.  I have removed everything from my cupboards and have cleaned with bleach, but even after 5 weeks I still keep finding them on the counter. How do I get rid of these little bugs? I believe they are called Liposcelis bostrychophila but I'm not totally sure. 


Book lice are tough little guys to get rid of, but it can be done without pesticides. Somehow, your cabinets have a high humidity level that needs to be reduced. Here's the information you are seeking.


Normally, control using pesticides is not needed if strict sanitation is practiced. If all else fails you may consider using a product like Tri-Die Aerosol or Tempo 1% Dust.

Liposcelis bostrychophila, also known as book lice, are part of the psocid family. There  are small, soft-bodied insects that feed on mold, fungi found in grains and other starchy materials. Book lice usually avoid light and like to live in cracks and crevices where the humidity is fairly high such as enclosed spaces like cabinets. You don't often find them inside unopened packages of products shipped from the manufacturer, but they do have a habit of getting into broken or opened packages and containers.

Reducing the humidity below 50% will eliminate most infestations of book lice. Try to ventilate high moisture areas using a dehumidifier or a fan. Be sure to use a crack and crevic attachment on a vacuum cleaner to remove bits of food  from the cracks of storage shelves. Don't overlook spilled foods like cereals and flour.

We are all guilty of pushing containers of food to the back of the shelf and forgetting about it. Foods stored for six months or more sometimes become infested especially in damp, dark, warm, undisturbed places. Try to rotate food products so that older items are used first. Check the manufacturing dates when you are going through your cabinets. Adult book lice populations tend to build up in greater numbers as the infestation ages. Put grain and cereal products in containers with tight fitting lids if the contents are not used within one week after opening. Place infested products inside plastic bags prior to disposal to reduce the spread of adult insects.

Ask Rick A Question


17 Feb 2014, 07:13
Hello exterminator, please help, I found book mites in our cupboard in and around food two weeks ago, I have had a pest control company come and deal with the problem, they have come four times and i have removed my kitchen cupboards, in the hope i will get rid of them. My question is could they be living in the blocks/concrete? Do they come from outside? My fear is that they will spread. The Pest control company used "actiobiol". Is there something stronger that can be used?

Thanks in advance
Ask the Exterminator
17 Feb 2014, 11:31
Read the article and you will see pesticides are not needed to stop book lice.
Alexis Van Dyne
28 Mar 2014, 23:26
My friend had booklice in a bag of chocolate chips in her cupboard and she's been eating out of it at night and she just thought the bugs were crumbs. Are booklice going to affect her health if she ate them? Do you think she should go she a doctor?
J. Seldon
28 May 2014, 07:19
To the guy that has them in electronic devices.

I have psocids that live in a TV! They used to hang around window sills as well before I cleaned those areas. Sometimes I see them crawling around my computer and landline too. This is ridiculous.

We barely had any mold and I have eliminated any all mold sources possible, yet these shitlings still find something to feed on. When fed the insides of their bellies turn white. In contrast, if you have black mildew for them to feed on their bellies will go black when fed. I have absolutely no idea what they could be eating unless it's the white wall paint or something.

So far, we've only seen them in a living room corner where the TV is. No crevices there, no mold under the carpet, nothing been spilt on the TV either. Besides, it's almost always dry in my place, yet they have somehow been breeding over the past year (even though not in large amounts I must admit).

These things are pretty smart for what they are. They easily spot humans and then quickly run back to their crevices (backside of the TV in my case). I guess I'll have to disassemble my TV to see what's up otherwise I am crap creek without a paddle.
04 Aug 2014, 19:41
We returned from 1 week holidays to find crawling creatures like shown on your page in the kitchen in Delta, BC. We used supermacro mode on the camera to see the details of the insect. They are everywhere in our kitchen, but not anywhere on the island. The largest grouping was in the toaster, which had a bread basket stored on top. They have been found in cabinets containing spices, medicine, recipe books, dishes, ...
We found them in tortillas [where we think we got the critters from as we have never bought flour tortillas before and never had these critters till now].

We recently had a carpenter ant problem this spring, so the idea of high humidity in walls is a real potential. but we have had hear record high temperatures for the past few weeks. Current outdoor temp and humidity is 26C and 55% so reducing the humidity to below 50% is not a possible solution.

We have removed everything from cupboards including shelves and sprayed a mixture of 0.25% Pyrethrins & 1.01% Piperonyl Butoxide into all cabinets and crevases. We have disposed of all flour products in packages. We are washing all dishes, utensils, and cooking equipment. The microwave, hood fan, dishwasher, and fridge have been sprayed but are not so easy to disassemble. We plan to wash all containers with food in them with bleach and remove lids to clean the cap and threads with 8% sodium hypoclorite bleach mixture.

How do kill the eggs, larvae, live bugs?
Do I need to freeze them to some particular temp for a certain amount of time? The freezer would accomplish this.
Will exposure to heat, sunlight, ... cause them to die? ? The sunny climate right now would help with this.
Without food how long can they live? Can we just quarantine everything for a specific period of time without a food source to kill the colony?

Please help.
25 Aug 2014, 16:42
Today when cleaning out my daughters room I found about 15 small white bugs that I had to look real close to see it was moving. It was smaller than a grain if salt. I found the in my daughtets bookshelf that has doors. I actally hound them om my daughters winter boots. I was cleaning out old shoes thst dont fit . Could they be book lice.? You had to really focus to even see them move, they were that small . It looked like a speck of dust. I dont like bugs at all esp in my home. After finding them I vacumed the book case and washed the boots in hot water. After that I went right online to try and findout what they could be an im thinking book lice.
06 Sep 2014, 18:56
Dear exterminator, I live in London,England and my block of flats (apartments) seems to have a problem with psocids. I get them in all rooms but never in my food cupboards as I keep all open packets in plastic boxes.

What I would like to ask you is, in the English climate are psocids likely to live on the outside walls and come in through the windows if I leave them open at night?

Thank you
Ask the Exterminator
06 Sep 2014, 20:23
All insects come from the outside to the inside. Windows without screens are sure to invite insects.
03 Feb 2015, 14:44
Why don't you answer the many questions people ask in full?? Please!!?

Thanks! ....A sufferer of booklice!
Ask the Exterminator
03 Feb 2015, 18:46

This is a box for comments. It's a place where visitors can share thoughts. Sometimes I add a response, but not often. If you want to ask me a question, click on the "Ask Rick a Question " link at the top of the page.
millie soto
14 Mar 2015, 23:43
Please help I been getting anxiety attacks . I think the are book lice like people say. my landlord thinks they are sugar ants but they are not I don think so. but the are thousand of them on my dinning room table on my counter, walls,electrical sockets . please tell me how to kill them. before I go crazy. thank you.
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