

Silverfish and firebrats (also called bristletails) cause damage in

homes by eating foods and other materials that are high in protein,

sugar, or starch. They eat cereals, moist wheat flour, any paper

where there is glue or paste, sizing in paper (including wallpaper)

and bookbindings, starch in clothing, and rayon or silk fabrics.

They can cause some damage in libraries, but they are primarily a

nuisance pest.



Description and habits



Firebrats are slender and wingless. They are greatly flattened and

broad at the front, tapering gradually toward the rear. They are

covered with scales. Adults are 1/3 to 1/2 inch long. Silverfish

are shiny and silver or pearl gray in color; firebrats are mottled

gray. The young insects look like the adults except that they are

smaller.



Firebrats have two long, slender antennae at their head end and

three long, tail-like appendages at the hind end. Each appendage is

nearly as long as the body, hence the name bristletail. Silverfish

and firebrats are active at night and hide during the day. When

objects they hide under are moved, they dart out and seek other

hiding places. They are swift runners.



Where found



Most species live outdoors under rocks, bark and leaf mold; in the

nests of birds or mammals, and even in ant and termite nests. In

the U.S., two species of bristletails are common in homes.

Silverfish live and develop in damp, cool places, especially

basements. Large numbers may be found in new buildings where the

walls are still damp. Firebrats live and develop in hot, dark

places, such as around furnaces and fireplaces and in insulation

around hot water and heat pipes.



In apartment houses the insects follow pipelines from the basement

to rooms on lower floors to find food. They may be found in

bookcases, on closet shelves, behind baseboards, and behind window

or door frames. Homeowners often find them in bathtubs, which they

enter seeking food or moisture, and then can't escape.



Development



SILVERFISH AND FIREBRATS
Silverfish and firebrats develop slowly under usual house
conditions, and have few young. They are hardy, and can live
without food for several months. The females lay eggs at any
season. They usually lay eggs in secluded places, such as behind
books or on closet shelves; occasionally they lay them in the open.

Silverfish lay only a few eggs at once; they may lay several
batches over a period of weeks. The eggs are whitish, oval and
about 1/32 inch long. They hatch in two to eight weeks. The length
of time they take to hatch varies with the temperature.

Firebrats lay about 50 eggs at once; they may lay several batches.
The eggs are soft, white, and opaque when laid. Later they have a
yellowish tinge. They hatch in about two weeks.

Firebrats reach adult size three to 24 months after hatching. Their
rate of growth depends on the temperature and humidity of their
environment. Several years are required before the female reaches
sexual maturity.

Silverfish and firebrats can be controlled by using commercially
prepared sprays or dusts that contain Dursban, diazinon, lindane,
or propoxur. Always follow label directions. Control with sprays
and dusts may not be immediate. If the spray or dust is properly
and thoroughly applied, it will leave a residue that will control
the insects in a few weeks. If some degree of control is not
achieved in 2 or 3 weeks, a second and more thorough treatment is
advisable. Be sure to treat cracks and crevices with the residual
spray or dust.

How to control them

Often control of silverfish and firebrats is possible by a thorough
cleaning, including vacuuming cracks and crevices in the area of
infestation. Removing moisture sources and drying out or
ventilating areas they frequent are also useful measures.

Dewey M. Caron
Extension Entomologist
7/94
.
