by Barb Ogg, Extension Educator
and firebrats 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 on which there is glue
or paste, sizing in paper (including wallpaper) and book bindings,
starch in clothing, and rayon fabrics.
and Habits: Both of these insects are slender, wingless,
and covered with scales. Adults are one-third to one-half 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. Both insects have two long,
slender feelers at their head end, and three long, tail-like
appendages at the hind end.
and firebrats are very common in homes throughout the United
States. Both are active at night, hide during the day, and avoid
direct sunlight. When objects under which they are hiding are
moved, they dart out and seek other hiding places.
silverfish lives and develops in dark, damp, cool places, especially
basements. Large numbers may be found in new buildings in which
the masonry is still damp. Because silverfish require and seek
a moisture source, they are frequently found trapped in sinks
and bathtubs. However, they may be found in bookcases, around
closet shelves, behind baseboards, and behind window and door
frames. Silverfish are often brought into new homes in cardboard
cartons, books, and papers from infested sites.
contrast, the firebrat lives and develops in hot, dark places:
for example, in attics, around furnaces, ovens, and fireplaces,
and in insulation around hot water and heat pipes. It prefers
areas where the temperature is 90o F and above. Temperatures
below 32o F and above 112o F readily kill
immature stages of this pest.
control of silverfish and firebrats, three non-chemical control
tactics should be considered:
Change the physical environment in the immediate ares of infestation.
For example, controlling or eliminating moisture (e.g. leaky
plumbing, around laundry areas, etc.) where a silverfish population
is thriving can be quite effective in significantly reducing
the level of infestation.
Reduce the potential sites of harborage. Seal obvious and easily
accessible cracks and crevices. Do not leave silverfish and
firebrats preferred places to hide and breed.
Remove potential food supplies, specifically paper, book bindings,
starched linens, and organic debris. If these materials cannot
be secured in tightly sealed containers or cabinets, make sure
your pest control application cuts off access of these pests
to potential food sources.
liquid, dust or bait formulations can be used for silverfish
and firebrat control, liquids are usually preferred in exposed
areas of the home where dusts or baits may present a hazard
to homeowners or pets. Currently registered liquid insecticides
and their rates of use for silverfish and firebrat control include
the following: propoxur, chlorpyrifos, bendiocarb. The effectiveness
of residual sprays often can be enhanced by using them in conjunction
with short-lived contact sprays, such as pyrethrins (resmethrin,
allethrin). Pyrethrins irritate the insect which causes them
to run over an area on which a residual spray has been applied.
Pyrethrin aerosols are conveniently available in grocery stores.
Residual insecticides usually provide 15-45 days of control
and should be applied to the areas where the silverfish and
firebrats are most commonly seen. Because both insects prefer
to hide or rest where there are tight cracks or crevices, particular
attention should be given to injecting small amounts of insecticide
into cracks and crevices formed by shelving, loose moldings,
or floor tiles. Spray around baseboards, door and window casings,
bookcases, shelving, closets, and in other storage areas, and
places where pipes go through walls or floors. Spraying only
the warmer parts of the building is usually sufficient to control
provide exceptional control of silverfish and firebrats, although
they are more visible and can move from the original site of
application. As a consequence, dusts can be used effectively
in attics, dry crawl spaces, basements, and other places where
their use is not potentially hazardous. Commonly used dusts
currently registered for silverfish and firebrat control are
insecticides such as amorphous silica gel, boric acid, bendiocarb,
and diatomaceous earth. Pyrethrin dusts can be used but have
shorter residual activity. Dusts are best applied with a hand
duster, although boric acid dust can be obtained in an aerosol
formulation. Inject dusts into cracks, or spread a thin film
wherever the appearance of the deposit will not be objectionable.
governing the use of pesticides are subject to constant change.
Therefore, it is important to use the insecticide only as specified
on the label. (updated
March 27, 2001)
for more information on Silverfish