Silverfish and Firebrats Phillip E. Sloderbeck Entomologist Southwest Area Office Introduction bers and they may leave yellow stains, Silverfish and firebrats belong to especially on linens. They can be a the order Thysanura or bristletails. problem in libraries and other places Bristletails are primitive insects that where books, documents and papers owe their survival to their secretive are stored. life in the soil, under stones, in leaf litter, and in homes and buildings. Silverfish Silverfish have a distinct body form They hide during the day and are called thysanuriform. They are spin- Firebrat active at night. Homeowners find dle-shaped: broad at the front end and bristletails when objects are moved as long as seven years. It may take up taper to the rear. They are wingless and the insects scatter to seek a new to two years for silverfish to become and covered with scales (except when hiding place. They also are noticed adults. Silverfish can withstand long very young). The name silverfish or when they crawl into a bathtub or sink periods of starvation. Some specimens fishmoth comes from their fish-like and cannot escape. These insects feed have been reported to live 307 days appearance. They have long, slender on a variety of materials including pa- without food. The female silverfish antennae and three long, antennae- per; glue and paste in book bindings; lays between 50 and 150 eggs during like appendages at the tapered end of wallpaper paste; starch in clothing; her lifetime. The eggs are laid sin- the body, hence the name bristletail. cotton, linen, and rayon fabrics; wheat gly or in small groups and are either Immature silverfish look exactly like flour; breakfast cereals; dried meats; randomly distributed or in concealed adults, except for size. Adult silverfish and even dead insects. Bristletails are places near food. The eggs hatch are inch long. There are three a nuisance pest, but they also consume ½ to ¾ in three to six weeks depending on species of silverfish that commonly food and contaminate it with their temperature. The first nymphal instar infest houses: the common silverfish body scales and droppings. They can lasts seven to 10 days and successive (Lepisma saccharina), the gray silver- damage some natural and synthetic fi- molts occur every two to three weeks fish (Ctenolepisma longicudata) and depending on temperature. the fourlined silverfish (Ctenolepisma lineata). Firebrats The common silverfish lives in The firebrat (Thermobia domestica) damp, cool places. In homes, it is looks similar to the silverfish. Fir- generally found in the basement, ebrats are mottled in shades of gray, around the plumbing, and beneath or white, brown and black, and adults are Common silverfish behind cabinets in the bathroom or about ½ inch long. This insect is found kitchen. Gray silverfish can be found only in extremely warm places such as throughout the house even in dry areas furnace rooms, fireplaces, ovens and such as crawl spaces and in the attic. bakeries. This species does not repro- The fourlined silverfish may be found duce unless the temperature is above in extremely dry or moist conditions 90°F. Temperatures below freezing or inside and outside the home. These in- above 112°F kill immature firebrats. sects have a long life span. Some live The female lays approximately 50 Four-lined silverfish Kansas State University Agricultural Experiment Station and Cooperative Extension Service eggs during her lifetime. Under good product labeled for the intended use. conditions, the firebrat may complete Treatments should be applied to all a life cycle in 11 to 12 weeks. The hiding places such as cracks and crev- average life span of this insect is 1 ices in basements, around baseboards, to 1½ years. Because firebrats molt cupboards, closets and around pipes. throughout life, they may pass through Before using any insecticide, read 40 to 60 molts and can regenerate lost and follow instructions. Contact a pest appendages. control professional when infestations are persistent and hard to find. Pest Control control professionals are licensed Prevention: Sanitation is an impor- and certified to apply restricted use tant step in controlling silverfish and insecticides that are not available to firebrats. Be sure to remove old stacks homeowners. of newspapers, magazines, paper, books, fabrics, foodstuffs and spilled food products. Sometimes, especially for the common silverfish, reduc- ing available water and lowering the home’s relative humidity with dehu- midifiers and fans can help. Lighting a dark, sheltered area may force these insects to seek hiding places where they can be controlled more easily. These insects normally enter the home in food, furniture, old books, papers and old clothing. Be careful when bringing these items into your home from infested locations. Pesticides: Sanitation alone often is not enough to control serious infesta- tions. Insecticides containing allethrin, bifenthrin, boric acid, carbaryl, cyper- methrin, deltamethrin, esfenvalerate, permethrin, D-phenothrin, prallethrin, propoxur or resmethrin are labeled to control these pests. Be sure to select a Photos courtesy of the Kansas Department of Agriculture Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, credit Phillip E. Sloderbeck, Silverfish and Firebrats, Kansas State University, November 2004. Kansas State University Agricultural Experiment Station and Cooperative Extension Service EP-123 November 2004 K-State Researcch and Extension is an equal opportunity provider and employer. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, as amended. Kansas State University, County Extension Councils, Extension Districts, and United States Department of Agriculture Cooperating, Fred A. Cholick, Director..