Of the thousands of species of cockroaches in the world, 30 are considered as pests to humans. And of those, 3 are commonly found in North America and can infest our homes and restaurants. They are the German, American and Oriental cockroaches. They feed on human or pet food and waste and are especially drawn to rotting food, often carrying diseases on their bodies and are linked with allergic reactions in humans. These allergens are also linked with asthma.
The most notorious cockroach and frequent invader in our homes is the German Cockroach (actually originating from southern Asia), Blattella germanica. A light brown or tan in colour with black stripes, the German is 1.3 to 1.6cm long and are winged insects but rarely fly, preferring to quickly scutter.
German roaches are often found living grouped together, close to kitchens but also bathrooms and basements but not often seen during the day, liking to scavenge for food at night. In addition to typical food and garbage, they will also eat cardboard, paper and books and sometime even soap and toothpaste. The German cockroach breeds very quickly, their colonies growing to impressive numbers if left untreated. If you detect a musty or foul odor coming from the areas they congregate, it is likely that you have a large population on your hands.
American Cockroaches are medium to dark reddish-brown and have a lighter, tan or yellow band on the back of the head. Growing to 4cm in length, they are the larger cockroach often depicted in cartoons and advertisements but not as commonly seen indoors. They are winged and though more likely to fly than than German Cockroaches, they like temperatures to be warm enough for the task.
American cockroaches prefer dark, warm and moist areas like basements, foundations and sewers (they are sometimes referred to as waterbugs or sewer roaches) and while more typically seen outdoors, they will enter buildings in search of food, preferring spilled food and droppings, crumbs, garbage or other decaying waste.
At about 2.5 to 3.2cm long, the Oriental Cockroach is shiny, black or dark reddish brown and is more similar in habitat and feeding to the American than the German, preferring the same dark and damp conditions.
More often living outdoors, they typically live under mulch and leaf litter or debris in yards and gardens eating decaying organic matter. As a result, they can thrive under porches and in storm drains, sometimes entering homes in wall crevices but prefer areas that are undisturbed.