Evidence Identification
Reading pest signs - droppings, damage patterns, cast skins, frass, and other evidence to identify species and infestation severity even when pests not visible.
Detailed Overview
PCOs must identify pests from evidence since many are nocturnal or cryptic. Droppings: Cockroach droppings look like ground pepper or coffee grounds, smaller for German roaches, larger for American roaches. Mouse droppings pointed at ends, 1/8-1/4 inch, scattered. Rat droppings blunt ends, 1/2-3/4 inch, clustered along travel routes. Bed bug fecal spots are dark dots on mattress seams absorbing into fabric. Damage patterns: Termite damage follows wood grain creating galleries. Carpenter ant damage has clean galleries, sawdust-like frass piles. Rodent gnawing shows paired incisor marks. Cast skins: Shed exoskeletons indicate cockroach or bed bug harborage nearby. Frass: Termite frass is tiny pellets pushed from galleries (drywood termites). Carpenter ant frass contains wood shavings, sometimes insect parts. Rub marks: Greasy smudges along rodent runways from oil in fur. Urine stains: Rodent urine glows under UV light. Live/dead insects: Collect specimens for ID. Evidence tells story: fresh vs old (color, moisture), quantity indicates severity, location shows harborage and travel routes, pattern reveals species. Photograph evidence during inspections for documentation.
When to Use
Inspect for evidence during every service call. Learn to recognize species-specific signs. Use evidence to confirm pest ID when live specimens not observed. Assess evidence freshness to determine current vs past activity.
Required Skill Level
Should only be performed by licensed pest management professionals
Benefits
- Identifies pests without live sightings
- Reveals hidden infestations
- Determines severity from quantity of evidence
- Guides inspection focus to active areas
- Species-specific evidence confirms identification
- Fresh evidence indicates current active infestation
Limitations
- Requires experience to interpret correctly
- Similar evidence from different species confusing
- Old evidence misinterpreted as current activity
- Some pests leave minimal evidence
Related Concepts
Other principles that may be useful
Integrated Pest Management (IPM)
A prevention-based pest management method that provides long-lasting pest control, improves building conditions, and is less harmful to residents and pets than traditional pest control.
Pest Triangle
The four essential requirements pests need to survive: food, water, shelter, and ways to get around. Eliminating any of these makes an environment inhospitable to pests.
Threshold Levels
The point at which pest populations or damage reaches a level that requires action. IPM uses threshold levels to determine when treatment is necessary rather than treating on a schedule.