About half the German cockroach jobs we attend have already had a bomb set off, sometimes three or four. The customer saw dead cockroaches on the floor the next morning, felt relieved, and then saw live ones in the bathroom a fortnight later. That is not bad luck. It is how those products work against this insect.
First, check which cockroach you have
German cockroaches are small, about 12 to 15 millimetres, light brown, with two dark stripes behind the head. They live indoors all year, in warm, tight places close to food and water: fridge motors, dishwasher surrounds, microwave vents, cupboard hinges. The big dark cockroaches that wander in from the garden or the drain are a different animal and a much easier job.
What a bomb actually does
A fogger fills the room with a fine mist that settles on open surfaces: benches, floors, the tops of cupboards. It does not travel into the cracks where German cockroaches spend most of their time.
- It kills the ones caught in the open, which are a small share of the total.
- The mist irritates the rest, so they move deeper into the walls and into the next room.
- Egg cases are protected. Each one holds 30 to 40 young, and they hatch after the mist has gone.
- It leaves residue on the surfaces where you prepare food.
Foggers are also flammable. Setting one off near a gas pilot light or a running fridge motor is a real fire risk, and the label says so.
What works instead
German cockroaches are beaten with bait and cleaning. Gel bait is placed in pea-sized dots or smaller, right where they hide. They eat it, go back to the harbourage, and others are affected there too. An insect growth regulator stops the young ones from maturing and breeding.
Your part matters as much as ours:
- Clean the grease from behind and beside the stove and the fridge.
- Fix dripping taps and dry the sink overnight.
- Store food in sealed containers and empty the bin each night.
- Do not use surface spray near the gel. It puts them off the bait.
Be ready for a second visit
Even done properly, one visit rarely finishes it. Eggs hatch over the following weeks, so we come back at two to three weeks to rebait. You should see fewer after the first week and very few after the second visit. If you share a wall with a food business, they may keep arriving, and the bait points need topping up through the year.
A treatment with the follow-up starts at $220.