Insect

Gray Silverfish

Ctenolepisma longicaudata

Low Risk

Biology

Ctenolepisma longicaudata is a large silverfish 13–19 mm long, uniformly grey with very long antennae and tail filaments. Unlike the common silverfish it tolerates normal indoor humidity and can live up to eight years.

Behaviour

Nocturnal and secretive, it grazes on cellulose, paper, book bindings, wallpaper paste, textiles, and dust containing skin flakes. It disperses through wall voids and is often spread in cardboard and second-hand books.

Habits

Damage appears as surface etching and irregular holes in paper, photographs, and stored textiles, with yellow staining and shed scales. It frequents bookcases, storage rooms, archives, and skirting-board voids.

Control methods

1Reduce paper and cardboard clutter in storage areas
2Seal skirting boards, wall voids, and service penetrations
3Keep relative humidity below 50 percent with ventilation
4Store documents and textiles in sealed plastic boxes
5Use monitoring traps to map harborage before treatment
6Apply labelled residual dusts to voids and behind baseboards

Tailored to Gray Silverfish

IPM Procedure Checklist

View full procedure

Step 1

Inspection

Inspect harborage near food, water and warmth
Check cracks, voids and appliance interiors
Place sticky monitors at suspected hot-spots

Step 2

Identification

Confirm Gray Silverfish (Ctenolepisma longicaudata) — not a look-alike
Note life stage and risk level: Low
Capture clear photos and samples for the record

Step 3

Action Thresholds

Tolerate low-level activity outside sensitive zones
Act if activity moves indoors or near food
Review threshold seasonally with the client

Step 4

Prevention

Seal cracks, plumbing penetrations and wall voids
Eliminate moisture sources and standing water
Improve sanitation: sealed food storage, grease removal

Step 5

Control Methods

Reduce paper and cardboard clutter in storage areas
Seal skirting boards, wall voids, and service penetrations
Keep relative humidity below 50 percent with ventilation
Store documents and textiles in sealed plastic boxes

Step 6

Monitoring & Evaluation

Service monitors on schedule and trend captures
Re-inspect for Gray Silverfish activity at follow-up
Adjust tactics based on data; report findings to client