Integrated Pest Management

IPM Manual for Structural Pests in British Columbia

Chapter 7: Silverfish & Firebrats

Learning Objectives

When you have completed this lesson, you should be able to:

Identify silverfish and firebrats and describe their damage.
Describe a monitoring method for silverfish and firebrats.
Describe how to prevent infestations by reducing humidity.
Describe sanitation measures to prevent silverfish and firebrat infestations.
Describe the use of sorptive dusts to control silverfish and firebrats.

Identification

Silverfish and firebrats live outdoors, but when building conditions are warm and damp they may move inside and adapt to the indoor environment. Once inside, they can be moved around on items transferred from one place to another (i.e., on boxes moved from damp basements or attics into main living areas). They may also travel through heating ducts that originate in damp basements.

Silverfish and firebrats are similar, wingless insects.

Both:

feed on starches such as paste, glue, fabrics, cereals, or wallpaper with paste,
can go without food for several months,
prefer warm, moist areas (firebrats choose hotter areas than silverfish),
avoid light and are active at night,
leave yellowish stains on fabrics, and
are long lived (adults live from 1 to 2-1/2 years)

Both silverfish and firebrats are:

grey to greenish in colour,
have two long antennae, and
three long appendages extending from the tip of the abdomen

They differ in the following characteristics:

SILVERFISH (Lepisma saccarina)

up to 13 mm long
single rows of hair
prefer 22° to 27° C

FIREBRATS (Thermobia domestica)

up to 8 mm long
rows of hair in clumps
prefer 38 ° C

Monitoring

Detection and monitoring can be done by placing sticky traps in areas where silverfish or firebrats are suspected. Commercial cockroach traps or other sticky insect traps may be used.

Action Decisions

These are primarily nuisance insects. They do not cause direct damage to structures and have little effect on goods unless they are present in high numbers. They are also generally not a health concern, although the damp conditions that favour their development may be and should be remedied.

The tolerance of the clients for the insects will determine the need and timing of treatments. In an apartment building with a low population of silverfish, some residents may consider a single silverfish enough to warrant treatment, while others will not consider higher numbers a problem.

Prevention

Reduce Humidity

When silverfish or firebrats are found in a structure, it indicates excessive humidity. Reducing humidity is essential for long term control. The damp conditions should be corrected as soon as possible (they could lead to termite or carpenter ant infestations or structural decay). Leaking windows or those with regular condensation should be repaired. Effective long-term control may require improving ventilation, repairing leaks, installing fans or other moisture controls.

Sanitation

Important sanitation measures to prevent silverfish and firebrat infestations include:

store food and garbage in pest proof containers
keep cooking and eating areas clean
vacuum cracks and crevices free of lint, then seal or caulk the cracks
removed infested boxes and other material, and
vacuum thoroughly and restack items in storage areas

Controls

Traps

Sufficient control may be achieved by using sticky insect traps in areas of high humidity.

Preferred Pest Control Products

If pesticides are necessary, sorptive dusts such as diatomaceous earth or silica aerogel can be used. In dry areas, a light application of diatomaceous earth behind baseboards and in other cracks frequented by the insects can provide very good control.

Other Pesticides

In areas where sorptive dusts cannot be used, a crack and crevice application of any pesticide registered for this purpose will work.

Evaluation

After treatments, sticky traps can be used to monitor for silverfish and firebrats.