Bedbugs and Their Control

Scientific name: Cimex lectularius
Common names: human bedbug, wall louse, mahogany flat,crimson rambler


  • Color: mahogany brown
  • Flat, looks like a small watermelon seed with legs
  • Size: 1/5" (5mm) long x 1/8" (3mm) wide
  • Abdomen prominently segmented side to side
  • Can't fly; dysfunctional, atrophied forewings
  • Very fast runner when exposed to light (roach like)
  • Nocturnal
  • Eggs: white, 1mm slightly bowed; glued in place
  • Hatch in 6-10 days; longer if cool
  • 70 - 82° F optimal for eggs
  • Eggs die when temperature is less than 55° F or higher than 98.6° F
  • Nymphal instars: 5, each requiring a meal of blood
  • Lifespan: greater than 560 days



Food: blood
Survives months without food

  • Uncovered areas, e.g., ankles, neck, face
  • Painless
  • Similar to flea but no red center
  • Immediate red, itchy wheal
  • Often bites in approximate rows as if it cannot decide where to bite



Suspect bedbugs when the following is observed:

  1. Itchy bites but no fleas or mosquitoes in evidence
  2. Dwelling is co-inhabited by birds or bats
  3. Structure is used by transient populations
  4. Blood stains/red spots/smears on walls or curtains
  5. Black/brown spots (excrement) seen at hiding and resting places
  6. Quickly flip the mattress and look for running bugs
  7. Sickeningly sweet odor (heavy infestation)


Control Techniques

Phase 1

  • Call EH&S; to get pest control services: 206.543-7209.
  • Be able to positively identify pest (specimen).
  • Make certain bites are from bedbugs, not fleas or mosquitoes.
  • Clean up and de-trash the infested room.
  • Wash and dry all clothes and bedding on hot cycle.
  • Vacuum, dry clean, fumigate or discard infested mattresses.
  • Discard mattresses with torn seams, tears in fabric, deep crevices and seams, etc.
  • Replace with seamless mattresses with bug proof covers.
  • Prevent removal of bedding and furniture to other dwelling places until infestation is over.

Phase 2

  • Consider the adjacent rooms and the hallway as a single unit. Don't treat just one room. Bedbugs wander.
  • Ask residents on both sides of the infested room and across the hallway whether they:
    • are getting bitten and/or
    • have seen any strange-looking little bugs (show picture).
  • Remove and treat any bed boards or frames.
  • Expand treatment in concentric circles from bed(s).
  • Apply insecticide to all cracks and crevices in structure and nearby furniture.
    • Pyrethroids or equivalent to flush insects from hiding places.
    • A residual insecticide to provide longer term killing effect.
    • Re-apply periodically until certain that bedbugs are eliminated.
  • Also treat:
    • Cracks, joints in bed frames
    • Cracks in plaster, paneling, walls and wall paper
    • Sockets
    • Baseboards
    • Window and door frames
    • Pictures and wall hangings, lights mounted on walls
    • Furniture seams
  • Repeat above treatment several times even if no bugs are observed.
  • Replace wood bedsteads with smooth, seamless product.
  • Repair wall cracks, peeling wallpaper and any other likely hiding places.
  • Expect recurrences over a period of years.