Of all the insect pests, cockroaches are probably the most adaptable home intruder. They are also good at hiding their presence, as they often build their nests in dark areas that are free of vibration and noise. Finding this nest requires a little detective work and persistence on your part.
Place several sticky roach traps in areas where you have seen cockroaches or suspect cockroach activity. Traps should be placed along tight edges such as where the wall and floor meet. You should also place them under sinks, in cabinets and in corners.
Check the traps two nights in a row. Record the number of cockroaches caught in each trap.
Move traps to another location if no roaches are caught. Repeat Steps 1 and 2 until roaches are found.
Try to identify the type of cockroach caught in the trap. German cockroaches are 1/2 inch long, light brown and have a pair of parallel brown bars between the head and front wings. Brown-banded cockroaches look very similar to German cockroaches, but do not have the bars on their backs and have two light bands across their wings. American cockroaches can be up to 2 inches long and are mahogany coloured. Oriental cockroaches are dark-coloured and about an inch long. See the next section for suggestions on where to look for the different species.
Use the traps to tell you where to start looking. The nest is likely to be close to where the most roaches were caught.
Look for possible entry points for cockroaches. Cockroaches usually nest inside walls, baseboards and ventilation ducts. So, they need a crack or entry point into a room. You may notice fecal matter (similar to fly spots) around the area they are using.
Use your nose to help you find the nest. Most roach nests have a strong, foul odour that can be detected the closer you get to it.
Look for German cockroaches near plumbing fixtures in bathrooms or kitchens. They may also be found in cracks in cupboards or under drawers. They prefer warm, moist areas such as appliances and furnaces.
Look for brown-banded cockroach nests in areas that are warm most of the time, typically above 26.7 degrees Celsius. They don't need as much moisture as other cockroaches. They may be nesting inside radios, appliances, televisions or computers. You can also find signs of them behind pictures or on the underside of furniture and shelves.
Look for American cockroaches in dark, moist locations such as a furnace or boiler room. They are more common in industrial and commercial buildings than in homes. They are very common in sewers and areas above 27.8 degrees Celsius.
Look for Oriental cockroaches in cooler damp places usually under 28.9 degrees Celsius. They are more common in basements, crawl spaces and on the first floor of a building. They especially like areas under refrigerators, sinks, washing machines and floors.