Silverfish
What They Are
Silverfish (Lepisma saccharina) are wingless, carrot-shaped insects about half an inch long, covered in silver-gray scales that give them their name. They move in a distinctive fish-like wriggling motion and are strictly nocturnal — most homeowners encounter them when turning on a bathroom or basement light at night. They require high humidity (above 75% relative humidity) to survive and reproduce, making them reliable indicators of moisture problems in the areas where they appear.
Silverfish feed on starchy materials — paper, cardboard, book bindings, wallpaper paste, and natural fiber fabrics. A silverfish population in a basement storage area can slowly damage stored books, paper records, and fabric items over months without being noticed until the damage is significant. They don't bite and pose no health risk, but their presence signals conditions that also support mold growth and wood deterioration.
Earwigs
What They Are
Earwigs (order Dermaptera) are elongated brown insects distinguished by the prominent pincers at the rear of the abdomen. Missouri's common species reach about 3/4 inch in length. The pincers look alarming but earwigs rarely use them defensively against humans. Like silverfish, earwigs require moisture and are primarily outdoor insects that enter structures when exterior conditions become unfavorable — drought, heat, or excessive rain that saturates their outdoor habitat.
Moisture Reduction — First Line of Control
- Run a dehumidifier in basements and crawlspaces targeting below 50% relative humidity
- Ensure crawlspace vapor barrier is intact and covers full soil surface
- Check crawlspace vents — blocked vents accumulate moisture that sustains both species
- Move firewood, mulch, and leaf debris away from foundation — outdoor earwig harborage adjacent to the structure feeds interior pressure
- Fix dripping faucets and address any slow drain moisture under sinks
When moisture control alone doesn't resolve persistent silverfish or earwig pressure, D&D Pest Control provides treatment programs for Franklin County and rural Missouri — visit ddpestcontrolmo.com.