In Wisconsin, there are four common species and four occasional species of cockroaches. Traditionally, cockroaches are oval-shaped, flattened, reddish-brown to black in color, and around 1 1/8 to 2 inches long. They hide in dark, damp, confined places during the day and are active at night. This pest poses severe health risks once indoors, especially as an asthma trigger in children.

1. The most common cockroach in Wisconsin is the German cockroach. They have two dark stripes behind their head, and can be up to 5/8 inch long. They breed around three to four generations per year, making them the fastest breeding cockroach. This type of cockroach needs a source of water, and is often found in bathrooms and kitchens.
2. Next up is the adult Brownbanded cockroach. They are light brown to glossy dark brown, as the name suggests, and are about 5/8 inch long. They prefer warm temperatures of at least 80 degrees, so they are often found in false ceilings and around appliance motors, light switches, and picture frames. They have lower water needs than German cockroaches, so they can be found in any room.
3. The third most common cockroach in Wisconsin is the American cockroach. These cockroaches are reddish-chestnut brown in color with light markings behind the head and can be up to 1 ½ inches long. They are most likely to be spotted in large commercial buildings such as hospitals, grocery stores, and bakeries. They can also be found in warmer climates and is nicknamed things like “palmetto bug” and “water bug”.
4. The final, most common cockroach in Wisconsin is the Oriental cockroach. These cockroaches are dark brown to shiny black and can be up to 1 inch in length. They prefer cool areas with high humidity, so they are often found in damp crawl spaces, basements, and floor drains. Nymphs are found in spring and early summer, while adults are found in late summer.

The only native cockroaches in Wisconsin are the wood cockroaches. They look similar to small American cockroaches, are dark brown and up to 1 ½ inch long. They live under bark of dead trees and can be brought indoors with firewood. Male wood cockroaches can actually fly, and are attracted to lights at night.

As for the occasional cockroaches, the light green Cuban cockroach is often found in bananas. The Surinam cockroach is a plant feeding species found in greenhouses and tropical plants. The Australian and smoky brown cockroaches arrive in various shipments and pallets from the southern United States.

It is important for people to take preventative measures to protect their families and properties from the health threats associated with cockroaches. Cockroaches thrive in conditions of poor sanitation and areas where there is a large amount of food available. Following certain rules and eliminating those attractive environments can help prevent cockroach infestations.

Cockroaches are more difficult to control in apartment buildings. Some sprays simply repel the cockroaches and drive them into untreated areas. All units may need to be treated to prevent reinfestation. Tenants should keep trash rooms clean, and allow free access to pest control professionals.

As always, if you are experiencing a pest problem, we are happy to help.