It isn't that difficult to kill a single cockroach, but permanently controlling an infestation calls for an integrated approach that includes deterrence and exclusion strategies as well as methods for killing active roaches. Although no single method will eliminate all roaches, you can make significant headway by baiting and dusting with boric acid and by deploying gel-type insecticides in strategic locations.
Remove Their Food and Water
Cockroaches need food and water to survive and are likely to turn up in places where they find it. A roach can make a meal out of a few leftover crumbs, so eliminating their food supply isn't as easy as it sounds.
- Keep all food in insect-proof containers, such as jars or resealable plastic bags, especially when storing it in cupboards and drawers.
- Clean and vacuum the floor and countertops frequently. Wipe up spills before they turn into sugar-laden spots.
- Don't let your garbage pile up -- take it out before the bag overflows.
- Provide as much ventilation as possible in dark areas under counters and behind fixture -- such as the toilet -- to prevent condensation from forming.
Keep Them Out
Cockroaches sometimes come in on your clothing or your groceries, but more often, they enter through cracks in baseboards, floors and walls, and they hide in dark corners in drawers or behind counters. Start sealing these cracks outside, then seal indoor cracks and inspect your furniture carefully for eggs.
- Look for small cracks in the foundation and seal the cracks with caulk. If you can, spread a 6-inch-wide gravel barrier around your home's perimeter.
- Trim bushes, trees and shrubbery around your house. Any branches that touch the roof or the siding are roach bridges -- eliminate them.
- Inspect baseboards and walls around areas where you spot roaches. You'll probably find cracks large enough for them to enter. Seal the cracks with caulk.
- Check everything you bring into your house, including groceries, clothing, furniture and appliances. Pay special attention to anything that was recently in storage.
Bait or Dust Them
Although you can buy many different types of baiting traps for roaches, you can easily make your own, using boric acid, which is available at drug stores.
A bait typically contains less than 5 percent boric acid -- any more than that, and the insects won't eat it. Although there are many formulations, an effective one is to mix just enough of the powder with sweetened condensed milk to make a sticky paste. Put this bait out on waxed paper anyplace that you see roaches. In lieu of a homemade bait, you can also use a gel bait, which is easier to spread in hard-to-reach corners.
Dusting with Boric Acid
Spreading a fine layer of boric acid on the ground in places in which you see roaches is another effective way to kill them -- the powder sticks to the insects' legs, and they ingest it when they preen themselves. The layer has to be extremely thin for this method to work; if the roaches can see or feel it, they'll avoid it. An easy way to dust a fine layer is to put the powder in a plastic condiment container and blow out the dust by squeezing the container. Be sure to treat the voids and corners in cabinets, closets and corners of the room where you are most likely to see them. Remove items from cupboards or closets, give them a thorough cleaning, and then puff your dust directly into the cracks and crevices where roaches travel. Pay special attention to the backs of cabinets where they join the walls. This will provide long term protection from roaches.