Published in the Contra Costa Times on April 17, 2004

Q.  I have these little gray insects in my bedroom on my shelves. They move very rapidly.  Are they dangerous?  How do I get rid of them?

A.  Look closely at the books on your bookshelves. The sample you brought in is called a silverfish, a thin, wingless, soft-bodied insect about 2.1cm (½” long). There are about 13 species of Thysanurans in this country, their long  carrot bodies taper to the rear with short legs, long slender antennae in front and long, thin appendages in back  (anal cerci), which make them appear much larger. Their bodies are covered with scales.  These insects can survive for months without feeding, and are long- lived. Reproductive rate are moderate, so it can take a long time for populations to expand.

These are true booklovers; their common diet consists of book bindings or paper products where glue or starch was used. They can also feed on the starch in clothing, cereal and wheat flour.  These nocturnal pests can enter your home through openings such as light fixtures or heater vents. They are searching for food and water, so your bookshelves are ideal, although they can be found in any room of a house.   One of the traps used to confirm their presence uses a small jar coated with flour on the inside and tape on the outside to provide a climbing surface. The silverfish be become trapped in the jar. Place the jar in an area where you suspect silverfish of living, and check it regularly.

To discourage them from making themselves permanent residents, keep your home,  especially kitchens and bathrooms clean and dry. Putty around the spaces where pipes enter, and repair leaks to limit access to moisture. Clean out closets, paying particular attention to baseboards and dark corners where they like to hide.  Clean up piles of magazines and papers. Check that the food stored in the kitchen or pantry is in containers with tight fitting lids. Dust the books on the bookshelves.

 Several products are available that help with control, but pesticides are not needed if you only have a few silverfish. Cleaning thoroughly will provide good control, and blocking access will discourage other pests from entering. For more information:  http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7475.html