Keeping a Nigerian kitchen cockroach-free

Water first, food second

Most people attack the crumbs. Crumbs matter, but water matters more, because a cockroach can live for weeks on almost nothing to eat and only a few days without anything to drink.

So the first walk around your kitchen is a water walk. A slow drip under the sink, a bowl left soaking overnight, a dish rack standing in its own puddle, condensation behind the fridge, a mop head kept damp in a bucket. Each of those is a reason to stay.

Dry the sink before bed. Empty the rack. Fix the tap that has been dripping since last year. It is unglamorous work and it does more than any amount of spraying in the open.

They live in the gaps, not in the open

A cockroach wants to feel surfaces on its back and its belly at the same time. That is why it chooses the gap behind the cooker, the seam under the counter, the space behind a fridge motor, the inside of a cupboard hinge, the cardboard folds of a carton stored on the floor.

Pull the cooker out. Look behind the fridge. Take the cartons off the floor of the store and break them down, because corrugated cardboard is close to ideal harbourage and it is usually the thing nobody thinks to remove.

Sealing those gaps with filler where you can is permanent in a way that treatment is not. A gap you close is a gap you never have to treat again.

What you see at night is a fraction

Switching on the kitchen light and seeing two or three scatter usually means a good deal more are behind the units. Cockroaches are nocturnal and they come out in the open when the harbourage is crowded.

Seeing them in daylight is a stronger signal still. It generally means the population has outgrown the space it is hiding in.

Take it as information rather than as an emergency. It tells you the problem is a harbourage problem, and that clearing and sealing has to happen alongside anything you spray.

Treating a kitchen without contaminating it

Treat the harbourage, not the room. Directing a short burst into the gap behind the cooker, along the skirting and into the void under the units puts the product where the insects actually are.

Clear the worktop first. Cover or remove food, plates, cutlery, chopping boards and the kettle. Never spray onto a food surface, into an open pot, or across a preparation area.

Leave the room and keep it closed for the time stated on the label, then open the windows and let it air before anyone cooks. Wipe down any surface that will touch food.

Keep children and pets out until the room has aired properly. Read the label before you start, and follow it rather than this article where the two ever differ.