Via Cerberus:

We were having a problem in our garage with Oriental Roaches (aka “waterbugs”) these are the big black roaches usually found outdoors in yards near water sources. They were coming in under the garage door this summer to escape the heat and search for water. These traps were excellent for attracting and traping these roaches. In fact, I was replacing them every couple of days because they were full of roaches and also spiders and other insects. Just be aware that traps of any kind are helpful in lowering a roach population, but they will not eliminate them. Traps are also very useful in gauging how big of a problem you have.
To rid yourself of the Oriental roach or other species of roaches, you will need Advion Cockroach Gel Bait by Dupont. This is a relatively low toxcicity bait that will wipe out a roach infestation. It can be purchased from a number of DIY pest control websites and is the same stuff used by the professionals. Also very important in roach control
is the following list of things you need to do in addition to the bait mentioned above:

***Don’t let them in. Cockroaches may enter houses via sewer connections, under doors, around utility pipes, air ducts, or other openings in the foundation. They love cracks and can squeeze in just about anywhere. Young roaches can fit into a space as thin as a dime. An adult male needs a crack about the thickness of a quarter. Attach well-fitting door sweeps. Fill holes where pipes disappear into walls with silicon sealant, steel/bronze wool. Search for cracks along foundations, baseboards, pipes, windows, vents, cabinets and doors and seal larger gaps and dust smaller cracks with Boric Acid. Install or repair window and door screens. Install fine mesh screens over vents, ducts and floor drains. Keep sink plugs over drains in sinks, showers, etc., which are not used often.

***Keep them away from food. A roach can find a snack just about anywhere. They eat crumbs, pet food, dead leaves and trash. Store food in tightly sealed containers or in the refrigerator and put pet food away overnight. Don’t leave open bags of food or candy lying around. Clean up spills and crumbs right away, especially from under appliances, and wipe all counters and tables after use. Rinse food and drink containers before disposal, empty trash and recycling frequently, and use trashcans with tight-fitting lids. Clean your dirty dishes right away and keep the stove grease and food free. Wash or replace sponges and dishrags often.

***Keep them thirsty. Roaches need water to live. Without it, they die within a week even though they can live up to a month without food. Fix dripping faucets. Water yards in the early morning, not at night when roaches are active. Don’t over water yards. Prevent condensation from your A/C unit from pooling near your foundation.

***Make it hard for them to hide. Roaches spend most of their lives hiding. If roaches can’t hide, they’ll find someplace else to live.
Move woodpiles, stockpiled bricks and other clutter away from outside walls. Raise boxes and stored items off your garage floors and away from walls. Take your recycling out promptly; avoid letting old food cans, stacks of newspapers or magazines pile up. Use a light dusting of Boric Acid under appliances, under sinks, cupboards and other low lying areaas where roaches like to hide.