Booklice are small insects which love moisture. In general, they need to live where humidity is high or moisture is present. Common places for booklice populations to thrive include window sills, under outside siding of homes, tree trunks, shrubs, flowers, around garden hoses, under bricks and rocks, around light fixtures and under boxes. However, some species will readily live in books, book cases, attics and crawl spaces. As stated above, there are many families and species of this insect and the science community has not quite come to a concise conclusion about how to group and name all that are included. Some appear to have specific moisture requirements and others do not. At the same time some seem to be food specific and others do not. To make matters more confusing, it appears that booklices are able to change their dietary needs as food availability changes. One thing is for sure: If you have booklices active in or around your home – expect them to prosper and keep coming back unless the conditions which they seek are changed.



Booklice hatch from eggs in about 2-4 weeks after the eggs are laid. Young will go through about 2-4 nymphal stages to reach adulthood which takes another 2-3 months. Once mature, females can generate 50-100 eggs during her life and as an adult she would expect to live 1-4 months. Most populations will produce 2-3 generations per year but there could be a lot more if conditions are just right. Booklice are able to adapt to their environment which will dictate just how fast they reproduce. In general, the more moisture and the more moderate the temperatures (50 -80 degrees) the more they will prosper. Cold weather (below 35 degrees) will kill off adults but eggs will live ready to hatch as soon as local temperatures get back to where they are comfortable.



Booklice will eat just about anything. Though most people think they eat books or paper, in fact booklices can thrive on a wide range of food. Such food includes cellulose (paper or books), book bindings, fabric (from which many book bindings are constructed), glue (the glue that binds most books has many natural components), any type of grain, mold, mildew, algae, fungus and other plant life. The fact that booklices will readily live in books is the same reason they will readily live on trees: the presence of both cellulose (paper is made from wood) and fungus or algae. Algae or fungus will readily grow in damp dark places inside homes but it also thrives outside. It is here where local booklice populations will begin to accrue.



Once established alongside homes, they will commonly find adequate food supplies up underneath any type of siding on homes. From there they commonly find window sills to be great food areas as well as outside light fixtures, outlets, door frames, etc. The author has seen them thrive on just about any perimeter location of any structure which gets wet during rain or irrigation. Such areas have a tendency to harbor moisture and this harboring is what enables fungus and algae to grow. Once this growth starts booklices will soon follow.



The good news about booklices is that they are slow eaters. This means that damage from local populations is usually minor unless populations go unchecked for long periods of time. However, booklices are both annoying and persistent so most people don’t want them around. Fortunately, they are easy to kill and with the right products being used it is easy to manage or eliminate any activity in or around the home.

So before you treat, there may be some maintenance needed in areas where activity is noted.



1) Mold, algae and fungus removal will help slow up booklices. Remember, this is a key food item for booklices so by cleaning away and removing that which they eat will cut down on their reproduction.

Therm Humidity Monitor2) Reduce moisture in such areas. Though it is hard to stop rain from accumulating on window sills and other areas of the home, any attempt to channel water away and off structures will help to cut down on just how much fungus, mold and mildew can grow. By cutting down on this growth you will be able to cut down on booklice activity. If you are not sure of current moisture levels, get one of our HUMIDITY MONITORS. This portable device is an excellent tool for monitoring moisture in rooms and any area where pests like psosids are present.

Therm Humidity MonitorHumidity Monitor:


3) Once mold, mildew and fungus has been cleaned away and moisture levels have been reduced, consider sealing any apparent cracks or seams through which booklices may be entering or living. IT IS VITAL THAT MOLD, MILDEW, FUNGUS AND BOOKLICES ARE ALL TREATED BEFORE YOU SEAL. If you start to seal cracks without first addressing why they are wet, you may only be making a bad situation a lot worse. This will happen when moisture is sealed into siding and wall voids – a condition which many homeowners create when they randomly caulk. The rule is simple: Seal cracks and crevices only when you have first cleaned them out, treated them with one of the insecticides we will have listed below and are sure the moisture source has been addressed and that once sealed, it won’t get wet again.



Pump SprayerRough and ReadyTreating the mold, mildew and fungus is the first part of controlling booklices. Once local populations have been identified, use a product like ROUGH’N READY. This product is easy to use and will kill off all mold, mildew and fungus on which the booklices live. Use a rag to wipe down window sills and other small areas but if you have a large area to treat, use one of our PUMP SPRAYERS to get fast and rapid coverage. Be sure to wipe the product all around insuring complete coverage any where booklices have been seen. This product should be used on siding, window frames and sills, around door frames and anywhere moisture is a problem. Booklice which are thriving in books or other dry areas won’t require such treatments; as stated above there are several species of booklices and several are able to live where mold and mildew are not present.


Rough and ReadyRough’n Ready:

Pump Sprayer Eliminator Pump Sprayer:




PT 565 XLOOnce you have adequately reduced the mold, mildew and fungus on which booklices live, you have three types of treatment options. The one you choose should be made based on the type of surface being treated. If you have small areas to treat like a window sill or two, PT-565XLO will offer quick knockdown and ease of use. Because it is an aerosol, it won’t make a mess or require any time to dry. When used right it will go on dry and yet work immediately. PT-565XLO can be used on all books, record albums and any type of document or fabric as well.

PT 565 XLOPT-565:


Again, proper applications will not damage the treated surface nor will it cause discolorations or any “wet or oily” film to be left behind. It doesn’t take much of this product to get good coverage and the more sensitive the treated surface, the less you should use. Remember, this product is for small areas and may require treatments every few days. This is because the active ingredient, Pyrethrin, offers no residual. In other words, it will only kill when it is being applied. Within an hour or so all the active ingredient will have broken down and be gone. For this reason you will probably have to make several applications if you want to get rid of all booklices since the treatment will only kill exposed or hatched insects. It won’t do anything for eggs so it is best to schedule at least weekly treatments for 1-2 months to insure you have broken the cycle altogether.

PT-565 XLOPT-CykickFor areas where you can use a long lasting residual, go with the slightly stronger formulation called CYKICK AEROSOL. This product has all the same qualities as the 565 with the one big difference in length of residual. This aerosol uses Cyfluthrin which will last 2 or more weeks per application. The advantage to this is simple: Less frequency of applications and less product needed. It too can be applied over surfaces like fabric and books without causing treated surfaces to discolor or get wet. Be sure to lightly apply it since a little is all that is needed when treating. The only draw back to this product over the PT-565 is that it will not flush the booklices. Since they will have to walk over treated surfaces to pick up a lethal dose it is imperative that you treat as many of the cracks and crevices in which the booklices may be hiding. Only then can you be sure to have proper coverage otherwise you risk reinfestation. One way to avoid this is to first apply the Cykick thoroughly and then followup with the PT-565XLO. The 565XLO will flush the booklices out of where ever they are hiding since they don’t like this product which in turn will cause them to walk over the surfaces treated with the Cykick which will then insure they die. This 1-2 punch is sometimes needed when you have a large area to treat which involves a lot of cracks and crevices.



PT 565 XLOPT-565:




PT 565 XLOSolo Sprayer PT-Cykick CSIf you have large areas to treat like the side of walls, the house exterior, trees, shrubs, etc, the use of an aerosol product is not practical or efficient. For these areas it makes a lot more sense to use some type of liquid residual like PT-CYKICK CS. This odorless concentrate mixes with water and is applied with a PUMP SPRAYER over surfaces on which you have seen activity. It will provide both a quick knockdown and a long residual keeping hatching booklice eggs from thriving. PT-Cykick can be applied over the siding of homes, around windows, on trees and plants and just about anywhere booklice activity has been found. The advantage of this product over the aerosols is that you can do large applications quickly and your work will reward you with long residual. Remember, PT-565XLO will not provide any residual. Applications kill only when applied and immediately dissipate. The Baygon will last at least 1-2 weeks per application and if this isn’t long enough, use PT-Cykick since applications made with this product will last over a month. Remember, it uses water as the carrier so this product is not recommended to apply over books or other sensitive objects. Use the aerosol for such applications.


PT-Cykick CSCykick CS:

Solo SprayerSolo 454:

PT 565 XLOPT-565:




Once you decide on which product to use remember to stay with it and make applications throughout the season as needed. Generally speaking, infestations which are located outside will be active in the warm months and go dormant if you have a winter. For the southern most states, it is not uncommon to have activity year round. Most of these outside applications should be done with PT-Cykick CS. If you have found booklices in the home or building and have decided to use one of the Aerosols, expect to do several treatments since these applications will not last as long. Aerosols by nature will break down much faster than the liquid treatment and in fact the PT 565 XLO provides no residual. If using PT 565 XLO you will need to do treatments at least once a week if not more until all eggs have hatched and the cycle has been broke. The Cykick Aerosol will last longer and should provide 1-2 weeks between applications which will reduce the amount of work you need to do.

Booklice can be a persistent and annoying pest in and around the home. Though they don’t bite, their chewing mouth parts can cause a lot of damage to fabric, books, wallpaper and other inanimate objects around the home which are valuable. Reduce moisture levels to deter nesting and seal cracks and crevices where booklices may be entering for long term protection. Treat with any of the products listed above for immediate control and elimination.


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Comments on BOOKLICE CONTROL Leave a Comment

January 26, 2012

Valari Fanson @ 9:39 am #


I have a very large, old country home and I was going to use the PT-CYICK and spray the basement and upstairs, on the walls and counter tops. I was then going to follow up with the PT-565XLO aerosol. My question is, is it safe to spray on surfaces that I prepare food on? The booklice are on my counter and table and walls. Would it be alright to use this spray were we eat our food??

March 15, 2012

sufferer @ 5:45 am #


Hi, I wish to know if any of the above insecticides will result in moisture seeping into the wood and promote mould growth? In addition, after spraying them into the crevices, can I caulk up these crevices using clear silicone? Thanks!

April 9, 2012

NICKY @ 6:43 pm #


Can I use the spray on the kitchen walls? That’s where they are the most.

May 1, 2012

maz @ 9:57 am #


Hi and Thanks for all the info. My question is am I looking for a nest or colony? I find them all over my bedroom so do I have a mold problem on the outer walls and do I just presume they’re living and reproducing by the mold? How do I hunt the source? Please help as my newborn is in my room with me.

May 3, 2012

Julie @ 11:00 am #


Hi. I also am having a psocid problem. They haven’t migrated into our home yet, but they are attempting it as I have found them crawling around our doorways attempting to come in. My main problem is they are all over the outside of our house on the vinyl siding. The numbers aren’t too bad, but it is a lot more than I’ve noticed in years past. I am looking at getting some of the PT-Cykick CS and spraying down our house. I am wondering though; we live in a notoriously damp part of town. Is our yard the main source of our problem? When it rains, our yard stays moist for quite a while and it has rained a lot this year. We put down yard granules so could this have driven them over to the house? I’m hoping we don’t have mold growing under our siding. I have not ever seen them this bad in the 4 years we’ve lived in the house. Maybe the mild winter we had is causing this.

May 6, 2012

sally @ 7:11 pm #


Every room of my top floor flat is infested with tiny black specks called psocids. It is a brick building. The psocid love the inside of raw wood closets, drawers and wardrobes when they’re empty. All clothing and linen are in plastic bags. My area has had a lot of rain the past 3 years. Trees are very near the building and my side but my flat is dry. I can’t find mold or wet areas. Do you have a product that will eliminate them? 2 pest control companies didn’t work. Please help. Many thanks, Sally

May 7, 2012
June 25, 2012

Danielle @ 11:01 pm #


I am not sure if these are what I have. I notice them more at night. They are flat and very tiny insects in my window sills and I see them on the siding of the house. I need to know if these are what I have so I can get the problem taken care of.

June 26, 2012
July 6, 2012

susandgs @ 4:22 am #


I have booklice living in my air conditioner. What do I do. It is not one that I can remove.

susandgs @ 10:04 am #


Thank you for answering me. Please may I ask you another question. I live in Manhattan. I have never had any bugs so I was not “looking” for any. By the time I noticed these tiny bugs, they had invaded my desk which was in front of the air conditioner. They have invaded my printer and my fax machine. I put both in black garbage bags sealed as we speak. Do I need to throw them out? It is a professional printer and was rather expensive, but I WILL throw it out if you tell me I have to.

Also can I spray into outlets as they seem to be living in the outlet I was plugged into.

I am a wreck. By the time I even noticed them, there was a swarm all over the floor leading away from the desk area. I will tell you I am in tears as I write this.


Are they living in my (dry) carpet now also? I can’t tell.

Thank you for answering me.

susandgs @ 1:32 pm #


Thank you. So if I understand you, I do not need to treat the carpet?

July 16, 2012

Janice H. @ 7:50 pm #


I have a book lice problem in my bedding (mattress, blankets, and bed sheets), which is an area not commonly associated with booklice based on my internet searches. I’m wondering how to treat mattresses and bedding. I’ve tried washing all of the bedding in hot water and drying it thoroughly in the dryer but the booklice still appeared. Now I’m considering buying a plastic covering for my mattress and box springs, similar to what they use for treating bed bugs and dry cleaning all of my sheets and blankets. Would this be effective in treating book lice found in bedding? I live in a dry, desert climate but will also purchase a dehumidifier since my bathroom is en suite. Are there any other recommendations that you can make for treating bedding?

July 17, 2012
July 26, 2012

Amy @ 10:15 pm #


Last night as I was getting ready for bed I looked under the bathroom sink to get something and noticed very tiny flesh colored bug. I took everything out of the counter and sprayed everything down. I sprayed the counter, the floor, the walls, even the doorway leading into our bedroom. Today my husband sprayed our whole house molding on top and bottom, floors, windows, doorways. I haven’t seen them anywhere else in the house. What do I need to do to to keep them OUT of my house. We have an old house and we spray every 3 months to avoid this problem. Did I find them in time to keep them from spreading throughout my house?

July 27, 2012
July 29, 2012

brenda @ 5:49 am #


I have booklice everywhere in my ground floor flat which is owned by council. Its an old cornish unit building. It’s very damp. They are in my sofas, beds, wardrobes, clothes, walls, cupboard under the sink in kitchen and food cupboard. They are driving me mad. Can you help please? The council won’t. Thank you.

September 21, 2012

Janice @ 1:17 pm #


@Tech Support:
The insect I thought were booklice were identified by an entomologist at my pest control company as springtails. I think this is correct since I noticed that the insects in my home were quite jumpy, almost like fleas, but I had read that booklice don’t jump. I’m still confused as to how they are living inside of my home since I live in a desert climate and the relative humidity inside of my house, including near the bathrooms and kitchen, (measured with a hygrometer) is often in the 20-30% range. Is the treatment you recommend for booklice also effective in treating springtails?

October 27, 2012

Rob @ 1:17 am #


We live in Southern California and our entire home is infested with booklice. We had our local entomologist identify them as our local pest company claimed they couldn’t do anything for booklice. We are desperate for any suggestions and what spray to use. We have been fighting this infestation for over 4 months now and they are in every room all over our furniture and some window sills etc… We have no idea where they are coming from but I’m assuming from under the baseboards, behind the walls. What products would you recommend for us to use throughout the entire house? My fear is that they have also nested in our furniture, bed, books… I’m scared that we will take them with us when we decide to move. Any suggestions? Thanks so much!

Rob @ 12:21 pm #


@Tech Support: Thanks so much for your reply! I will definitely get those products you listed above. Is it safe to assume that if booklice are all over our furniture including couches and beds that they have nested there? Since they are literally in every room on almost everything, should we spray each book/item with 565 before packing it up to move? It seems tedious to have to go through all our things but we really don’t want to take those critters with if they are nesting/hiding in our belongings.

Also, our home inspector mentioned that our home has moisture in our under the home crawl space (both neighbors also have this issue). No leaks though, but it seems like a perfect breeding area for them as it’s both dark and moist. Will spraying outside of home and inside baseboards/windows eventually take care of the booklice infestation or is it a matter if figuring out exactly where they are nesting or spraying under the house too? How many cans of Cykick would you recommend for 3 bedrooms, 2 bath, and 2 large living rooms? Thanks again!!

Rob @ 5:07 pm #


@Tech Support: Great, thanks! We’re a bit relieved after reading that you say it’s pretty easy to get rid of them. Last question – is the 565 safe on furniture such as couches, beds etc… and is the Cykick safe on hardwood floors? Thanks again! Very thankful we found your site.

October 28, 2012
November 3, 2012

Dan @ 1:58 pm #


Read through the article and all comments. We have booklice throughout our entire home. Sounds like for inside the house we need to spray Cykick first on all baseboards/windows and cracks. Is that correct? Then spray immediately after with pt-565? Is the pt-565 supposed to be used in the same way as Cykick (baseboards, cracks etc…) or is it more of a fogger that you spray in the middle of the room? The product label says to leave windows/doors closed when spraying which is why I’m confused how to use this product as I thought it’s better to ventilate the room. Also, we have booklice in pretty much everything we own (books, picture albums, couches, beds) – what can we do to get rid of booklice on such items without them being ruined? Thanks!

Dan @ 2:46 pm #


Also, what is PT-PI for? Noticed it’s also for booklice but seems you recommend Cykick and PT-565 instead? Thanks for clarifying.

January 20, 2013

Anonymous @ 6:58 pm #


We have a book lice issue in our current home and we had one in our previous home. They can be seen in all rooms, on walls and on floors. We keep low moisture levels and a dehumidifier going even in the cold winter months. Our humidity in the house is in the 30’s and they are still around. We don’t know where they are getting in.

We have no signs of mold or leaks or moisture issues in our 1 year old home. We keep all plastic bins up off the floor in our unfinished basement. We keep a very tidy house because of these things. Right now during winter we are seeing them mostly in the basement and in the open stair case coming up. We just cannot figure out where they are getting in.

I am seeing 10-15 a day right now as I check with my flashlight. In our previous home which was only 4 years old, we sprayed foam in the sill boxes thinking they were coming in there but it didn’t seem to improve. What can we do to finally get rid of these things??? I am just very surprised we are still seeing them in the cold midwest winter time.

February 13, 2013

Sheri @ 10:19 pm #


Hi, I have a whole bunch of these booklice in my moldy bathroom. They’re on the walls and ceiling and there is 2 corners where many of them line up and crowd up.

My bathroom has no windows, no exhaust and no fans so it gets pretty steamy in there during the winter when we have to use an electric heat and we keep the door closed until all the people (5 to be exact) have taken a shower. This usually takes about 2-3 hours; hence, the humidity can get quite high which I’m pretty sure is why the mold is forming.

OK, so back to the bugs; which sprays/products are safe to be used in the bathroom and how/when to use the products? I would like to get rid of the booklice, then try to maintain it so to prevent them from coming back for the time being so I could look into getting a dehumidifier or have a fan/exhaust installed.

Thanks in advance.

February 19, 2013

Guest @ 12:48 pm #


We have an issue with booklice, springtails and clover mites. Is there a product that will take care of all three inside the house and outside the house? And in the fall we get a lot of boxelders and some stinkbugs. Looking for a product that will kill and not repel which tends to just spread them around more. And something with long residual effect but yet safe for use around kids. And for outdoors; something that will hold up to the sun beating on the house and rain. Also a product we can treat the yard with. So I am guessing there are a few different products we will need to treat with but just don’t know what ones.

February 21, 2013

Bang @ 1:08 am #


Hi, I have some booklice problems in my bathroom ceiling. Which product would be right for use on the ceiling? Most aerosols are directed to be used upright, so would the 565 or cykick aerosols still be ideal to be used spraying parallel to the ceiling? Also the cykick aerosol is ONLY for cracks and crevices and can’t be used on wide space such as a wall? If the cykick aerosol is ok for wide spaces (walls), would the residuals be harmful if touched after application?

May 11, 2013

Sheri @ 12:33 pm #


I have a bathroom problem. Should I be using the 565 to kill off the booklice and then use the rough n ready to wipe the molding walls? Is it ideal to use the rough n ready with a pump sprayer in the bathroom?

June 24, 2013

Jennifer S. @ 4:21 am #


I have read all of your suggestions, and I don’t want to make you repeat yourself, but I have found book lice in my bathroom up stairs, and in my daughters bedroom, which probably means they are all over upstairs. I have three small children and I want to know how to safely and effectively get rid if these things. I am sure they are in the carpet, and since our house is very small, we have things stored everywhere. My other biggest concern is, we get Pharaoh Ants and we were told not to spray for other bugs because this would break up the colony and make matters worse. So, I am really wondering how to combat book lice, without messing up the situation with the Pharaoh Ants.

I don’t have the ants yet this year, but I have the proper bait, perhaps after two years of the professional bait, the colonies have died, but I am afraid to attract anything while killing these book lice. I have a springtail problem too, but its not an infestation, well it is outside, but I am more concerned inside right now and keeping cost low. Can you help me? Thank you in advance for your help.

August 31, 2013

Anonymous @ 5:35 pm #


We have a really bad booklice problem in our garage. What can we do since we can’t really control humidity in the garage. We are in WI. They are crawling all over everything, storage bins, toys, shelving, tools etc. Will they die off once winter comes around? To wash and clean everything in the garage just would not be possible and it would just continue to collect dirt. HELP!!

September 16, 2013

L. Smith @ 5:54 pm #


How do I kill any booklice deep inside my old books? They do smell musty since I stored them in a basement, in cardboard boxes. I had no idea the insects would spread throughout the house! I have small children and pets, so I like the fast depreciating 565, but I’m not sure it will penetrate inside the books which is where I have seen the insects.

They are old, out of print books, so I’d hate to throw them away although at this point they are no longer valuable. I thought I could put them in plastic bags with your pesticides but it sounds like they could live inside the book and not have to come out to make direct contact with the poisons. Also, I saw one in my box of old photos. Do I have to try to take every photo away from it’s backing to treat them? Many photos are a hundred years old. What do you reccommend?

May 13, 2014

Kay @ 1:38 am #


Hi, I think I have an infestation of booklice in a bedroom. There is a crack in the corner of the wall where the booklice are coming out of. I hoovered them away but more keep coming out of the crack. It’s horrible. I assume the mould is inside the crack somewhere but I don’t know how to get to it. What should I do to get rid of this problem? I’ve ordered a dehumidifier to use in the bedroom but I don’t know if it will get rid of the mould. :(

October 19, 2014

M. Byington @ 11:45 pm #


I have a new straw bale home. We live in rural Colorado at 7000 ft elevation. I am finding psocids all over the counter in one bathroom. A moisture meter was used on every single bale of straw showing it was under 14% humidity. Over the straw is cement and stucco. The psocids like the marble tiles and the grout on my bathroom counter. The counter is clean, the tiles and grout have been sealed. I can’t find where they’re coming from. We have even opened up the wall in a couple of places thinking that the bales were too wet somehow. The moisture content is now under 10%. I’ve looked under the counter, around the plumbing, on the walls and I cannot figure out where they’re coming from. I have killed literally thousands of these things. Got any ideas how I can find their nest in a new, clean, cement walled and stone countered bathroom? Permethrin knocks them down but they still keep coming. Thousands. It’s ugly.

October 20, 2014
November 20, 2014

Jose @ 9:52 am #


I live on the 17th floor in a condo. Last June I discovered that my kitchen drain was leaking and it caused the wooden floor to swell and buckle. After the repair I ran a dehumidifier for most of the summer. This Fall we noticed tiny bugs coming from the seperations in the floor wood tiles and in the corners around the baseboards. I assume these are booklice since I know the subfloor must have gotten wet and now moldy. I have tried filling in the spaces between the wood tiles with silicone to prevent the bugs from coming up and the humidity in my condo now is at 16% but they still are there. They are so small like the period at the end of sentence. I think I need to replace the floor but that is expensive- is there any way to get insecticide down into the subfloor? What else can I do?

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