The American, German, Oriental, and brown-banded cockroach species are categorized as the four primary cockroach pests of homes in the United States. These species are considered the most important cockroach pests in the country because they are the only ones that can be found in all states in the contiguous US, and they have been inhabiting the country for a longer time than all other endemic cockroach pest species. Because of these factors, these four cockroach species are also the most commonly controlled roach pests within homes throughout the US.
The American and Oriental cockroach species both prefer to dwell outdoors, but they live in close association with humans, and they frequently enter homes where they can establish reproductive populations, resulting in extensive infestations. The German and brown-banded cockroach species are the only two roach pests in the country that dwell primarily indoors. This makes the German cockroach the most commonly encountered roach species within homes and buildings in most areas of the US. Although the brown-banded cockroach is also a domestic roach species, they are becoming more scarce throughout the country for reasons that are not entirely understood. Because of their increasing scarcity, the brown-banded cockroach is not encountered within homes as often as the other three primary cockroach pest species.
According to a 2012 study, the American cockroach is the most commonly encountered roach pest within Houston homes. This study also revealed that American cockroaches favor attic spaces over all other indoor locations for establishing populations. The American cockroach is easily the largest roach species in the country, as both males and females grow to be between 1 ¼ to 2 inches in length, and sometimes larger. Given their commonality within attics, American cockroaches are able to disperse throughout entire homes, unlike German and Oriental cockroaches, which both prefer to establish harborages in first floor kitchens and bathrooms. Since American cockroaches enter homes from their usual outdoor habitat, insecticide barriers around the perimeter of homes work well to prevent invasions. Low-toxicity residual insecticides, and certain baits can also effectively control American cockroaches. Keeping vegetation around foundations neatly groomed, covering crawl space openings, and using silicone-based sealant to cover cracks and other potential entry points on the exterior walls of homes will go a long way to prevent infestations.
Have you ever found cockroaches in your attic?