Why sticky monitors outperform visual inspection
Visual inspection by even a skilled professional misses a significant fraction of cockroach activity. Cockroaches are nocturnal and spend 75–90% of their time in harborages. A daytime visual inspection catches only surface evidence (droppings, casings, oothecae) and the rare individual caught in transit. A 48-hour sticky monitor deployment captures individuals that are active at any point during that period — providing a significantly more complete picture of activity distribution. In Metro Vancouver restaurant audits conducted by The Wild Pest, sticky monitors consistently identify active harborages that visual inspection alone misses — particularly in upper cabinet areas, behind large equipment, and in secondary harborage zones that a visual sweep at eye level would pass over.
Trap types and selection
Sticky monitor traps for cockroaches come in two primary formats. Flat glue boards are inexpensive, simple to deploy, and effective when oriented correctly along baseboards. Folded tent-style traps (such as the Pro Pest or Catchmaster formats) provide a covered, darker space that is more attractive to cockroaches (which prefer to enter enclosed spaces) and provide weather protection in damp environments. For residential monitoring, flat glue boards from any hardware store are adequate. For professional restaurant monitoring programs, folded tent traps are standard because they are more attractive, more durable in kitchen environments (oil and grease resist the glue board surface on flat traps), and provide a more contained capture for species identification. Pheromone attractant additives are available but generally not necessary for German cockroach monitoring — populations at levels detectable by monitor are already motivated foragers.
Placement principles
Cockroaches run along edges — baseboards, wall-floor junctions, under cabinet edges. They do not cross open floor space if they can avoid it. Sticky monitors placed in the open centre of a floor will rarely capture cockroaches regardless of population level; the same monitor placed flat against the base of the kick-plate under a refrigerator will capture dozens of individuals per week in a heavy infestation. Placement rule 1: always place monitors against a vertical surface (wall, appliance side, cabinet base). Placement rule 2: place as close to documented or probable harborage sites as possible. Placement rule 3: in multi-trap programs, number and map each trap — the distribution of captures across traps tells you where the harborage centre is located.
- Behind refrigerator, flat against the motor housing back wall.
- Under stove, against the back wall.
- Under dishwasher, against the side cabinet panel.
- Inside lower cabinet under sink, flat against the back wall.
- Along the baseboard in the corner nearest the stove.
- Inside the base of the tall pantry cabinet if present.
- Under bathroom vanity against the back wall near plumbing.
- In laundry room if applicable — cockroaches frequently travel via laundry room walls in multi-unit buildings.
Reading capture results — what the numbers mean
| Captures per trap (48h) | Interpretation | Recommended action |
|---|---|---|
| 0 across all traps | No active foraging — possible early-stage, deep harborage only, or no infestation | Continue monitoring weekly for 3 weeks; inspect for other evidence |
| 1–3 total across all traps | Low-level activity — early infestation or single migrant(s) | Deploy gel bait at trap locations; escalate monitoring frequency |
| 4–15 total, concentrated in 1–2 traps | Moderate, localized harborage | Professional assessment; gel bait + IGR at harborage |
| 15–50 total, spread across 3+ traps | Established moderate infestation | Professional multi-visit protocol; building-wide notification in multi-unit |
| 50+ across multiple traps | Heavy infestation | Urgent professional treatment; building coordination essential |
Using sticky monitors to track treatment progress
Sticky monitors are equally valuable as a treatment evaluation tool. Deploy traps at the same numbered, mapped locations at every monitoring visit and track captures over time. A successful treatment will show a declining capture trend across visits: high counts at week 0 baseline, significant reduction by week 2, near-zero by week 6–8. If captures plateau or rise between visits, this indicates either a persistent untreated harborage, bait palatability decline (requiring active-ingredient rotation), or reinfestation from an adjacent source. The trend data is what justifies treatment adjustments — it is far more actionable than a technician's 'I didn't see many' on a visual inspection.