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Pest Control/book lice


QUESTION: Hi Jack, I wrote to you a few days ago but now have a positive diagnosis of booklice from 2 different extermination companies who saw the bus "live" when I brought samples. I had an air conditioner leak and water came onto my parquet wood floor. The tiles buckled but eventually flattened out.

When I use the Dustbuster, I empty the contents on a white paper and there must be thousands. I first spotted one on my laptop, the initial ones were dark but all I see now are nymphs and within 10 minutes of each vacuuming, I see about 20, so there is a real infestation. They are on my floor. I was supposed to get an exterminator but everything I read online said not to, just to lower the humidity. I am vacuuming constantly, washing the vacuum and filters. I do see a lot of dead ones but still way too many live ones.

Here are my questions. The humidity now is between 28 and 30. I have central hear that blows so leaving that on. But the room temperature is now 80. Is the high heat defeating the purpose? I also have an air conditioner so can regulate this but need your advice. What is the ideal room temperature?

I removed all of my books, vacuumed them and examined them. It's the floor that's the problem. I am vacuuming all day. How long will it take for them to die if I leave the humidity at 30 or so? I am getting so crazy seeing these on the white paper every time I dump the contents of the vacuum. Is there a safe spray or anything I may have at home that I can spray all over? I have been using Windex, vinegar and Murphy's but don't know if adding moisture is making it worse. I don't want anything that says a bunch of warnings. This stress level is getting to me, I feel like they will never stop multiplying. Thank you so much.

ANSWER: Susan,

Temperature should not make much difference. The important point is to maintain the area as dry as possible. Don't focus on a particular humidity. The main problem seems to be the anxiety these critters are causing in you. Keep in mind that booklice are basically harmless but if they are triggering severe anxiety this can be unhealthy. Have you discuss this with your MD? Don't resort to insecticides as they won't be very effective and can be hazardous if not used correctly.

Jack DeAngelis

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QUESTION: I didn't discuss this with my MD...I will be okay. I keep a clean house and it's very disgusting to me to think that if I am barefoot, these things are crawling all over the floor. I read other posts and the general consensus is that people feel like they're going to crack after a while. I know they're harmless but it's just grossing me out at this point. I want them out of here. I am sorry to bother you again but two of the question I asked weren't answered. If I keep the humidity at 30 (right now it's 26, I switched from the heat to the air conditioner), about how long would it take for them to die? I read about how they lay eggs and I am thinking if one lays that many eggs, and I have a few hundred...will this ever end? Second queston: I won't use chemicals but is there something natural I can spray on the cracks to help kill them? Thanks again!

I did answer the question about humidity, it should not matter as long as the area is kept reasonably dry. Booklice need mold and dampness promotes mold growth. There are no hard and fast answers. I also can't recommend using any insecticides (anything, natural or synthetic, that kills insects is an insecticide) in this case. Try to think about dealing with the anxiety rather than the booklice themselves.

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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