The first 24 to 36 hours
Foraging cockroaches find bait quickly — often within a few hours of nightfall on the same day it is applied. Depending on infestation level, the first dead insects appear within 24 to 36 hours, typically near harbourage rather than out in the open.
Do not judge the treatment by what you can see on the floor. The meaningful signal in the first two days is bait consumption: check whether your dots are shrinking.
Why day 2 can look worse
It is common to see more cockroaches on day 2 than before treatment. Affected insects become disoriented and leave harbourage in daylight, which makes a shrinking population look like a growing one.
This is the point where most people reach for a spray and undo the programme. Resist it — spraying near bait points contaminates them and repels the foragers that carry the active back to the nest.
- Increased daytime sightings on day 2 to 3 usually means the bait is working.
- Do not clean away or move bait dots that are being consumed.
- Do not spray, fog or use repellent products anywhere near bait points.
Day 3 to 5: the top-up round
By day 3 the heaviest-traffic dots are often gone. Replace consumed bait and add points to any location where consumption was high — that is the population telling you where the harbourage is.
Heavy infestations need this second round. Skipping it is the single most common reason a treatment stalls at 70 per cent control.
Everything below assumes a professional-strength bait — our cockroach gel kits ship with the applicator and placement map referenced here.
Day 7 to 14: colony collapse
With bait maintained, a typical domestic German cockroach infestation shows a sharp fall in activity by day 7 and near-zero sightings by day 10 to 14. Because egg cases are unaffected by bait, keep bait available for a further two to three weeks so newly hatched nymphs feed as they emerge.
Heavy or multi-room infestations, and commercial sites with several zones, run on the same curve but need more gel and a longer maintenance tail.
- Day 1 to 2: bait found and consumed; first mortality.
- Day 3 to 5: top-up round; sightings begin falling.
- Day 7: sharp reduction in activity.
- Day 10 to 14: near-zero sightings; maintain bait for hatching nymphs.