Although American, oriental and brown-banded cockroaches are common all over North America, the ones you're most likely to see in your kitchen are the relatively small German cockroaches. They often enter the house on clothing and in shopping bags, and once inside, they gravitate to the moisture- and sugar-rich environment of the kitchen through small cracks in the walls and floor, and procreate prolifically. Controlling them involves a combination of removing attractants, excluding them, and killing them with baits and dusts.
Don't Show the Money
It's only natural that cockroaches, like all living creatures, are attracted to the riches of abundant food and water. Turn your kitchen into a cockroach desert, and they'll probably go elsewhere. This is going to involve extra work for you.
- Keep food and liquids out of reach in insect-proof plastic bags, jars and other containers.
- Clean all spills promptly and thoroughly.
- Vacuum frequently to remove crumbs that may seem insignificant to you, but which are a bonanza for the roaches lying in wait to scoop them up.
Raise the Drawbridge
It usually isn't enough to remove attractants. Roaches are hardy and can usually out-wait you, jumping in for a quick feast whenever your cleaning efforts lapse. You also need to exclude them.
- Look for crevices and cracks in baseboards, especially in places where you see roaches, and seal them with caulk.
- Seal gaps around water and drain pipes that protrude through the wall.
- Remove clutter from inside your cabinets. Roaches hide in small spaces, and the more spaces there are, the more roaches will take advantage of them.
- Take peeling labels off canned goods and label the cans with a felt-tip marker. Baby German and brown-banded cockroaches can hide under the labels and in extreme conditions live off the glue.
- Remove debris, such as firewood and rocks from the building foundation, to take away hiding places.
Ready, Aim, Fire!
Despite your best deterrent and exclusion efforts, you'll probably still have to trap or kill some roaches to end the infestation. Your efforts will be most successful if you combine methods and concentrate them in areas the roaches frequent.
Vacuum Visible Roaches
Vacuuming roaches is such a simple way to catch them that you may not have even thought of it. Use a vacuum accessory with a restricted orifice to increase suction. While you're at it, remove droppings, which look like specks of pepper.
Trap Roaches in Jars
Coat the insides of empty jam jars with petroleum jelly, tape paper towels to the outside and put peanut butter or banana peels in the bottom. Roaches can easily climb into the jar on the paper towel but can't climb out again. Simply put the jar in the freezer to kill the roaches and use it again.
Dust with Diatomaceous Earth or Boric Acid
Food-grade DE is safe for children and pets, and it lacerates the skeletons of roaches that walk through it, killing them by desiccation. Boric acid is more toxic and should not be used in places where children or pets can come into contact with it. It gets on the legs of the insects, and they ingest it when preening themselves, ultimately dying of damage to the stomach and digestive system.
To be effective, dusts must be applied in a super-fine layer, or the insects will avoid the dusted area. Blow the dust from a plastic bottle or a bellows rather than spreading it with a spoon.
Bait with Boric Acid or a Gel
Gel baits containing hydramethylnon or abamectin are also effective -- deploy these along the tops of baseboards and deep in the corners of your cabinets.
You can also use commercial bait stations. Monitor and change the bait often; roaches tend to hide in bait stations when they dry out. Baits take some time to work, so be patient; it may be a week or two before you notice a significant reduction in the cockroach population.