RSS Feed
Email this article
Printer friendly page

Ask Rick A Question


Summary: Psocids are very small insects measuring 1 to 4 mm. They are more commonly called booklice and their presence may be a sign of a mold problem in your home.

The oldest psocid fossil was found in Kansas and was thought to have lived about 290 million years ago, or 284 million years before man made his first appearance. So, no matter what you do, you cannot expect to totally defeat the psocid.

Recommended pesticides are Demand CS, Tri-Die aerosol and PT 565 Plus XLO aerosol.

The psocid (pronounced so-sid) is a tiny insect measuring 1 to 4 millimeter in length. Its most outstanding feature is its long schnozola, or as it is better known, beak. Psocids are almost always gray, clear, or white and have long antennae. Some species have four wings, while others are wingless. Just when you thought you knew of all the flying pests, you learn about another one you want to avoid.


The bad news is that psocids procreate in large numbers. Booklice are always females and they lay between 50-100 eggs during their lives. The psocid covers its eggs with a silky thread that resembles a web. Psocids live about six months.

If you imagine a small critter, you probably think of lice, right? Then it is quite appropriate that some species of psocids are called barklice. This species clings to bark on trees and logs, and occasionally camps out under rocks.
The psocid feasts on pollen, decaying plants, and fungi, and even flakes of dead skin from humans and other animals. At least some something is profiting off of your sunburn and peeling skin from your vacation in Cancun. The psocid usually does not eat human food, but it will if mold is growing on it. Yet another reason to throw out the three-weeks-past-expiration-date cheese sitting in your fridge.

The smaller species of psocid, booklice, are commonly found around paper and books. They enjoy munching on the glue that binds books together. This psocid cannot hurt humans or animals, but they can become a problem because they tend to congregate in large numbers. In fact, they may gather by the hundreds or even thousands.

Besides paper products, booklice also feed on mold and fungi, especially in warm, moist places. So, if you discover booklice creeping around your house, it may be a sign that you have mold growing in your basement, bathrooms, or any other location with excessive moisture.


If you do happen to have a psocid infestation, the best way to get rid of them is to eliminate moisture in your home. Sometimes a fan will work, but a dehumidifier is your best bet. They thrive in relative humidities of 75 to 90 percent. Your goal is to lower the humidity to 50%. To avoid psocids or many other bug infestations, stack any boxes or storage containers off of the floor and away from dark corners. Fix that leaky hot water heater and eliminate any standing water.

Psocids can also become a problem during the summer months because they thrive in warm temperatures. In the winter, the mature psocids will die, but their eggs will hatch in the spring. As temperatures turn colder, be sure the firewood you bring inside is nice and dry. Moist firewood is sure to have psocid infestations.

Getting rid of mildew or mold problems will greatly increase your chance of killing psocids. If you have an infestation, you can't procrastinate about disinfecting your bathroom any longer. Insect sprays are deadly to psocids, so try using these on your new visitors. (Follow label instructions.) If barklice are living on your trees, a strong hose should do the trick to wash them away.

Ask Rick A Question


No comments yet
Notify me about new comments on this page
Hide my email
The box below is for visitor comments! Questions posted in this box may not be answered by Ask the Exterminator. For quickest response click on the "Ask the Exterminator a Question" link at top of this page.
Security Image:



More Articles Like This

  • Get Rid of Booklice
  • Book Lice
  • Booklice

  • Categories: