Cockroaches in an apartment: why one unit is never enough

Almost every cockroach found in South Shore apartments is a German cockroach. It does not live outdoors in Quebec: it depends entirely on a building’s heat, water and food. In a Longueuil or Brossard apartment building, it moves from kitchen to kitchen through ducts and shared walls, and that is what makes most treatments fail.

Identifying the German cockroach

The adult measures 12 to 16 mm. It is light brown, with two dark parallel stripes just behind the head, long antennae and spiny legs. Nymphs, 3 to 10 mm, are darker and wingless. The female carries a brown, oblong egg case until it hatches.

Not to be confused with:

• the Oriental cockroach, larger and black, which prefers damp basements and drains;
• a bed bug, smaller, oval and flat, with no long antennae;
• a cricket, recognizable by its jumping hind legs.

Signs of an infestation

• cockroaches scattering when the kitchen light goes on at night;
• small black droppings, like ground pepper, in cupboards and drawers;
• brown egg cases near the sink, dishwasher or fridge;
• shed skins and dead insects under appliances;
• an oily smell in a heavy infestation;
• cockroaches out in daylight: the population is already large and running out of hiding places.

The hot spots are always the same: the fridge motor, under the dishwasher, the cabinet under the sink, the microwave and the stove.

Why act without waiting

A German cockroach egg case holds several dozen eggs, and nymphs reach adulthood in a few weeks in a heated kitchen. A population can grow very fast.

The risks are well documented: contaminated food and surfaces, and allergens in droppings and shed skins that are associated with asthma in children. In a food business, a confirmed presence can also cause problems at inspection.

How treatment works

1. Inspecting the unit and its neighbours. In a building, the inspection covers at least the units on each side, above and below the one that complained.
2. Assessment. Size of the population, hot spots, routes between units.
3. Preparation. Grease and crumbs cleaned up, kitchen cabinets partly emptied, food stored in sealed containers.
4. Treatment. Gel baits placed in cracks and hot spots, often combined with an insect growth regulator that keeps nymphs from reaching adulthood. Repellent products are avoided, because they scatter the population instead of drawing it to the baits.
5. Sealing. Gaps around pipes, ducts and outlets between units.
6. Follow-up. Two or three spaced visits, with sticky monitors to measure the drop in activity.

What it costs

For a light infestation, a Québec generalist publishes an average cost of about $250, and about $350 for a standard spray treatment. For a heavy infestation needing several visits and often treatment of neighbouring units, the same source says the price can reach $1,500. No more local range is published for the South Shore. Sources are detailed on the pricing page.

The CD5 certificate in a kitchen

Gels and growth regulators are pesticides applied where you prepare food. In Quebec, the person applying them must hold a CD5 certificate from the Ministry of the Environment. Ask to see it, ask where the gels are placed, and have the quote state in writing what not to clean in the following days: washing away a gel bait makes it useless.

Keeping cockroaches from coming back

• Leave nothing to eat overnight: dirty dishes, crumbs, the pet’s bowl, an open garbage can.
• Fix leaks under the sink: water matters as much as food.
• Inspect second-hand boxes and appliances before bringing them into the home.
• Seal the gaps around pipes and outlets, especially on shared walls.
• Tell the landlord quickly: in a building, waiting gives cockroaches time to settle next door.

A restaurant, daycare or senior residence needs a documented program: see the commercial section. For rights and obligations in rental housing, see the frequently asked questions.