While it is well known that the relatively small-sized German cockroach is the most common of all indoor roach pest species in the United States, very few Americnans are aware that this highly successful species is considered the predominant roach pest in all human-inhabited regions in the world. This is not surprising considering that the German cockroach dwells solely within indoor habitats where they reproduce at far greater rates than all other roach pest species.

Well over 4,000 cockroach species have been described worldwide, and less than 1 percent of these species are considered pests. Unless a roach pest learns that food can be secured more readily and safely indoors than outdoors, the vast majority of cockroach pest species generally prefer to dwell outdoors. Of course, cockroach pests will also prefer indoor habitats in order to survive the freezing cold of winter.

Most roach infestations start after one, or multiple specimens wander indoors where they find a messy and unsanitary environment to be a survival advantage. Cluttered environments where dirty dishes and trash are abundant provide roaches with more places to hide from predators and a greater availability of decaying food. However, this is not the case when it comes to the German cockroach, as this species survives by maintaining indoor habitats. “Domestic” cockroaches are species that prefer to dwell solely indoors, and the brown banded cockroach is the only other domestic roach species found in the US. All other common roach pests in the US, such as the American, Oriental and the smokybrown species, are peridomestic species that travel indoors on occasion.

Of all roach pest species, the German cockroach is the most resistant to insecticides, making infestations difficult to treat. This species, like all other domestic roach species in the world, are relatively small, as they only grow to an average length of a half inch. Their small size allows German cockroaches to easily hide within tiny spaces where residents would never think to look. Their size also allows the pests to squeeze between cracks and crevices where they can access every room within a house or every unit within an apartment. This species’ nocturnal foraging activities also make them hard to detect within homes.

Since German cockroaches are largely resistant to all insecticides, infestations are often treated by modifying indoor environments to be less hospitable to the pests, but insecticides alone are insufficient for treating all types of roach infestations. Maintaining a trash-free and sanitary home, and inspecting indoor areas that are located near available food sources can sometimes suffice to eliminate infestations. Keeping dirty dishes from piling up in the sink is particularly important, as German cockroaches are known for their habit gravitating toward infested sinks. In addition to these modifications, recent bait traps have proven effective at reducing indoor German cockroach populations.


Have you ever experienced a German cockroach infestation?