American cockroach (Periplaneta americana)
Brownbanded cockroach (Supella longipalpa)
German cockroach (Blattella germanica)
Oriental cockroach (Blatta orientalis)
Pest description and damage Cockroaches are 1 to 1.5 inches long with long, thin antennae, brown to black, with or without strips or bands on the upper surface. The young look like small adults. The German cockroach is the most common roach around human habitation. It is 0.625 inch long at maturity with two dark streaks behind the head. The brownbanded cockroach is similar but with two transverse straps across the wings. The Oriental cockroach is about 1 inch long and very dark brown to almost black. They are very common in moist areas, such as basements, and will commonly come into homes that have slab floor construction. They will traffic along pipes within the structure and sometimes will be seen in the upper floors of a building. The American cockroach is large (1 to 1.5 inches) and reddish brown, most often found in basements or areas associated with high moisture.
Roaches move rapidly, live in cracks and crevices, avoid light, and are extremely successful at exploiting dwellings and food. German roaches can be brought into a structure in cardboard boxes or used appliances. Studies have indicated that roach allergens are a significant contributing factor in childhood asthma. It is best not to let a roach infestation continue without addressing it.
Proper identification of the species of cockroach is key to successful management.
Good sanitation is the most important factor for controlling cockroaches. Baits are one of the best products for homeowner use. Baits come in a variety of active ingredients. Place baits under sink, undersides of drawers, along baseboards, near water heaters, and under or near appliances and other places where roaches will most likely infest. Use of over-the-counter sprays, foggers or "bombs" are not recommended as they scatter the roaches throughout the structure and into adjacent units in multifamily dwellings. If baits do not provide the desired control, it is best to consult with a knowledgeable pest control company.
These roaches thrive in excessively moist conditions. Remove any fallen leaves or compost around the perimeter of the structure. Sealing around pipes and wires will help to keep them from entering a structure or using basement pipes to travel to other locations within it. A perimeter pesticide treatment can help keep roaches from entering a structure, but this should only be done after the above-mentioned control measures have been implemented.
For further information:
Cockroaches. National Pesticide Information Center. Oregon State University.