You wipe the counters, you take out the trash and you never leave dishes in the sink overnight. Yet the spot cockroaches like best in a kitchen isn’t the trash can or the pantry. It’s an appliance you open several times a day, and most people never think to check it.
In short
- The microwave and the oven top the list: they’re warm, they collect crumbs and grease, and they have dark corners.
- German cockroaches need warmth, moisture and food, and they gather in heat-producing equipment such as toaster ovens.
- Cleaning inside and behind your appliances takes away what they come for.
- Baits and boric acid work, but never inside electronics or on food surfaces.
The appliance they love
The Spanish news site OkDiario names two culprits: the microwave and the oven. “Both give off heat, tend to collect crumbs and grease, and have dark corners to hide in unseen,” the article explains. Cockroaches look for exactly that combination: heat, moisture and leftover food.
It isn’t only a matter of disgust. The hygiene company Ecolab, quoted by OkDiario, warns that cockroaches can spread germs such as E. coli and salmonella.
What US entomologists say
The picture is the same on this side of the Atlantic. Michael F. Potter, extension entomologist at the University of Kentucky, writes that German cockroaches “require warmth, moisture, and food, which is why they are most common in kitchens and bathrooms.” Beyond the cracks under sinks, he lists the spaces beneath and behind refrigerators, dishwashers and stoves, and adds that they “also congregate in clocks, toaster ovens, and other heat-producing electronic equipment.”
The pest control company Terminix notes that roaches can also settle in refrigerator seals and motors, and feed on old spills inside the fridge, the microwave or the stove.
The signs to look for
- Tiny black droppings, like grains of pepper or coffee grounds.
- Small brown, elongated capsules: these hold the eggs.
- Shed skins near the appliance.
- A musty, oily smell that gets stronger as the infestation grows.
How to take your kitchen back
- Wipe the inside of the microwave and the oven after use, as OkDiario recommends: splatters and crumbs are food.
- Pull out the stove and the fridge from time to time and clean underneath and behind them.
- Leave nothing out overnight: no dirty dishes, no pet food, and loose food goes in tight-fitting containers.
- Seal the gaps where pipes and wires enter walls with caulk, foam or copper mesh, as the University of Kentucky advises.
- Use baits the right way: stations flush against corners and cabinet edges, gel in many small dabs rather than big globs, and no cleaner sprayed nearby. According to Potter, roaches typically die within 1 to 3 days of feeding.
The limit
A spotless microwave won’t wipe out an established infestation: Terminix calls German cockroaches “notoriously difficult to get rid of.” Boric acid needs care too. The University of Kentucky recommends a fine layer “barely visible to the naked eye,” never on countertops or surfaces used to prepare food, and never inside electronic equipment, where the dust can damage the components. Keep baits out of reach of children and pets. If you don’t see a clear drop after a few weeks of baiting, call a licensed pest control professional.
Fall is also the season when other animals look for a warm shelter: here’s where snakes go in winter. For the greasy film that draws roaches in, try this baking soda, dish soap and sugar paste. And if your microwave is due for retirement, see the appliance more and more kitchens are replacing it with.
Warm, greasy and full of crumbs: clean the appliance, and you take away the welcome mat. That’s the trick.
