German Cockroaches
Blattella germanica
German cockroaches are the primary indoor roach problem in Alberta. They reproduce quickly, prefer warm tight spaces near food and moisture, and typically require bait-based, integrated control—not surface spraying.
What they look like
- Small, light-brown roach with two dark stripes behind the head.
- Nymphs are smaller and darker; they cluster in warm tight harborages.
- Usually seen at night—daytime sightings often mean higher pressure.
In Alberta, if you have an indoor roach problem, German cockroaches are the default assumption until proven otherwise.
Where they hide
- Behind and under fridges, stoves, dishwashers, and microwaves.
- Inside cabinet voids, hinges, drawer slides, and corner blocks.
- Under sinks and around plumbing penetrations.
- Bathroom vanities and warm utility chases in multi-unit buildings.
- Cracks/crevices near food, moisture, and heat sources.
Signs that matter
- Nymph sightings (especially very small nymphs) indicate active reproduction.
- Pepper-like spotting/smears in corners, hinges, and tight voids.
- Egg cases (oothecae) in protected cracks (often near harborages).
- Musty odor in heavy infestations and persistent nighttime activity.
Why infestations persist
- They thrive on tiny food sources: grease, crumbs, pet food, garbage.
- Warmth + moisture concentrates activity (kitchens/bathrooms/utility areas).
- Sprays used incorrectly can reduce bait performance or push roaches deeper.
- In multi-unit buildings, untreated adjacent units can re-seed activity.
The winning pattern is integrated: sanitation + bait + targeted void work + verification.
Common signs homeowners notice
- Roaches scattering when lights turn on (kitchen at night).
- Small roaches inside drawers, behind appliances, or under sinks.
- Droppings/spotting near cabinet corners and hinge areas.
- Activity increases after cooking, cleaning disruptions, or tenant turnover.
Common misidentifications in Alberta
Many occasional invaders can look “roach-like” at a glance. If you find a single insect far from kitchens/bathrooms with no spotting or nymphs, it may be an incidental outdoor insect rather than a breeding indoor population.
Bed bugs are flat and oval and hide in seams and upholstery. German roaches are faster, prefer warm kitchen/bath voids, and leave spotting in cabinet hardware and appliance areas.
What effective treatment looks like (high level)
- Confirm: identify species and map harborages (kitchen/bath priorities).
- Sanitation: reduce grease/crumb competition so bait wins.
- Bait-first strategy with targeted applications in tight voids.
- Supplement: targeted non-repellent work where bait can’t reach (as appropriate).
- Verify: follow-ups and monitoring until no-activity is confirmed.
Avoid “spray everything” approaches. Done wrong, it can scatter roaches and reduce bait uptake.