How do you get rid of cockroaches for good in Marrakech?

The German cockroach is light-shy: it avoids light and comes out once a room has been quiet for an hour or two. An inspection carried out at two in the afternoon shows nothing, even in a heavily infested home.

The observation protocol takes three nights and costs nothing:

1. At around one in the morning, walk into the kitchen without turning on the light, then switch it on all at once. Count what you see during the first two seconds, before they scatter.
2. Note where they run to, not where they were. The escape direction points at the harbourage, and the harbourage is what counts.
3. Do it again the next night in the bathroom, then on the third night behind the fridge and the oven.

Reading it is brutal and useful. Zero to three insects: an early focus, often confined to a single unit of furniture. Five to fifteen: an established colony, several harbourages.

More than fifteen visible in two seconds, or insects visible in broad daylight: the population has outgrown the capacity of its hiding places and is spilling over. That last case is not a question of cleanliness, it is a question of how long it has been running.

The same count is repeated after the treatment, at the same hours and in the same places. It is the only honest indicator you have, and it depends on nobody but you.

The point of biology that explains all the rest, and that almost no commercial page ever writes down.

The female German cockroach does not lay eggs one at a time: she produces an ootheca, a light brown horny capsule eight to nine millimetres long that she carries attached to her abdomen until a few hours before hatching. That capsule holds something like thirty to forty eggs. Its wall is impermeable: neither a gel, nor a residual spray, nor an aerosol reaches what is inside.

The timetable that follows, in the warm conditions of a Marrakech home:

• incubation of the ootheca: about three weeks, shorter in a hot kitchen;
• nymphal stage: several successive moults over six to ten weeks before adulthood;
• an adult female produces several oothecae over her lifetime.

The direct consequence: on the day of the treatment, part of the future population has already been laid and is out of reach. A single visit removes the mobile insects and leaves the capsules untouched.

Ten to fourteen days later a new generation is moving about, finds a gel whose palatability has dropped, and the infestation restarts. That is exactly the scenario described in this sector's customer reviews — "it worked for two weeks".

Which is why the date of the second visit is fixed on day one, before anything starts, and not when the client rings back. The principle holds for every species with protected eggs, including bed bugs, where the interval is longer.

Everyone puts the biscuits away. Almost nobody deals with the water, and water is the limiting factor.

A German cockroach survives several weeks without eating. Without water, it lasts a few days. In a climate as dry as Marrakech, the damp points in a home are rare, well known to the insects, and they concentrate the colony. Removing them does more to squeeze the population than three rounds of cupboard cleaning.

The list of real water points, in the order they should be dealt with:

• the defrost tray at the back of the fridge, permanently damp, thirty centimetres off the floor, sheltered and warm: the best spot in the kitchen;
• the sink trap and the dishwasher trap, and the flexible seal that joins them;
• the mop left standing in its bucket, the cloth folded over the edge of the sink;
• the dog's or the cat's water bowl left full overnight;
• the rim of the shower waste, and the lifted silicone seal that holds a film of water;
• condensation under a poorly ventilated worktop.

The evening habit that genuinely changes something: wipe the sink and the worktop dry, take the cloth out, lift the water bowl. It replaces no treatment, but it starves the colony while the gel does its work, and it shortens the overall duration.

Better said bluntly, because these remedies delay the call and let the colony double.

What does not work.

• Bay leaves, coffee grounds, essential oils: mildly repellent at very short range at best, and therefore counterproductive — a repellent moves a colony, it does not reduce it.
• White vinegar: a decent degreaser, not an insecticide. Its only real use is removing the scent marks along the trails.
• Ultrasonic devices: no demonstrated effect on cockroaches.
• Bicarbonate mixed with sugar: sometimes quoted as a lethal bait, it has neither the palatability nor the speed of a professional gel, and it does not pass through the colony.
• Foggers and total-release bombs: see below, this is the worst option of all.

What does have a real effect, as a complement and never on its own.

• Boric acid as a very fine powder, laid as an invisible film inside a dry, inaccessible furniture void: slow, but passed on through grooming. Unusable near food, children or animals, and useless if it is laid in a visible heap.
• Sealing up: silicone on pipe penetrations, fine mesh on air vents, draught excluders under doors. It is not a treatment, it is what stops your neighbour restocking you.
• The sticky trap with an attractant, not to kill but to measure: placed in the same spot before and after, it gives a comparable count.

Why gel beats an aerosol fits in one sentence: the gel is eaten and carried back into the harbourages, while an aerosol drives the insects away from the treated zones. The section on what brings them back returns to this.

What an honestly informed client sees, from day one to the fourth month.

Day one — diagnosis and first visit. Harbourages located, gel placed in discreet spots along edges, hinges, the backs of skirting boards and around ducts. Nothing sprayed into the air. Duration: one to three hours depending on the surface. The date of the second visit is written on the report before the technician leaves.

Days 1 to 3 — an apparent increase. You see more cockroaches than before, including during the day, often slow or disoriented. That is the expected behaviour: the gel brings out insects that never came out. Do not spray anything, do not wash the gel points. This is the exact moment when most people ruin their treatment.

Days 4 to 10 — the fall. The adults go first. The night count typically drops from several insects to zero or one.

Days 10 to 14 — second visit. It targets the generation hatched from the oothecae present on the first day. The gel is renewed at the points that have been eaten, and the secondary harbourages identified at the first visit are gone over again.

Weeks 3 to 6 — silence, then verification. A lone insect may appear: that is not a failure, it is a straggler. Three in one night is.

Months 2 to 4 — the monitoring period. This is where a written guarantee earns its keep: ask before signing whether the contractor will come back at their own expense if the same infestation returns in the same premises, and what they exclude — usually an external reintroduction, an untreated flat next door, premises they were refused access to.

Six causes, and they always come round in the same order.

1. A single visit. Cause number one, with no competition, for the reason set out above.
2. An aerosol used after the treatment. The repellent deposit drives the insects away from the gelled zones: the gel stops being eaten, and the colony scatters into the partition walls. A can bought "to help" cancels out the professional visit.
3. Cleaning the gel points. One wipe of a sponge along a skirting board removes the bait. Between the two visits, clean normally except at the marked points.
4. The untreated source. A building whose waste stack and bin store stay infested restocks the flats continuously.
5. Cardboard. Packaging cardboard is the number one vector of introduction: it is warm, it has gaps, and it comes from a warehouse. A delivery box does not stay in a kitchen.
6. A second-hand appliance. Fridge, microwave, coffee machine: cockroaches travel in warm electronic compartments.

Points 4 and 6 go beyond the boundary of one home. They belong to the building, like rodent control and the sealing of entry points, and they are settled with the managing agent or the owner.

In Marrakech, the density of the built environment and the shared services change the nature of the problem as soon as you leave the detached house behind.

Three signals say the focus is not in your home:

• oriental cockroaches — larger, blackish brown, slow — appearing in the bathroom or near a trap: they come from the drains, the inspection chambers or the void beneath the floor, not from your kitchen;
• a reappearance within a few weeks despite a complete treatment and two visits properly carried out;
• neighbours describing the same thing on the same floor or up the same riser.

In that case, treating a single flat is bailing out a boat. The right scale is the service riser and the common areas: ducts, refuse chute, bin store, basement, stairwell. That is a decision for the managing agent, and it works over time rather than one call-out at a time, with a calendar of visits set in advance.

For a shop or a commercial kitchen, one more constraint applies that a home does not have: written proof. An inspection asks to see a control plan, dated reports and a follow-up record, not an invoice for an intervention. The framework applicable to commercial premises is dealt with separately.

The checklist to keep in hand before signing any quotation, whoever the contractor is.

What they do: a diagnosis, at night or on the evidence, treatment with gel bait at targeted points, residual spraying reserved for perimeters and entry points, a dated second visit written into the quotation, a written intervention report, and a guarantee whose exclusions are in writing.

What they refuse to do:

• promise eradication in a single visit, whatever price is on offer;
• treat a home while refusing to say that the problem is in the building;
• spray an insecticide into the air of an occupied room for a visible effect;
• issue a certificate of sanitary compliance — an intervention report is not the same thing;
• announce a quantified efficacy rate, which cannot be measured in a home.

Ask for the safety data sheets of the products used and for the instructions on going back into the rooms, in writing, before the intervention.