Northern Plains Integrated Pest Management GuideIPM

Authors: Ashley Mueller, Buyung Hadi

Cockroaches are a very common insect, and they can be an invader of homes and buildings. They are medically important pests, and their presence indoors is a concern because they can cause health problems. They are able to transmit various diseases that affect the human digestive system. Cockroach legs and bodies easily spread disease-causing organisms to food, utensils, and surfaces.

Cockroaches undergo three developmental stages: egg, nymph, and adult. The nymphs often resemble the adults, but they are smaller in size. Cockroaches are highly adaptable to their surroundings. They are able to survive for a period of time without food and water. Active during the night, their flat bodies allow them to easily hide in cracks and crevices during the day. Determining the extent of cockroach presence is an important step in managing an infestation.

Identification

Dorsal view of an adult Oriental cockroach

Adult Oriental cockroaches (Blatta orientalis) are 1 to 1 1/4 inches long, and they are dark brown or shiny black in color. Adult females have short, triangular wing pads, and they are slightly longer than males. Adult males have fully developed wings. Both females and males are unable to fly. Compared to the American and German cockroaches, the Oriental cockroach is more sluggish in movement.

Habitat

Oriental cockroaches, often called water bugs, prefer dark, damp, and cool areas like basements and areas around sinks, drains, and washing machines. Usually they are found near garbage, sewage, or decaying organic matter. Very rarely are they found in high cupboards, on walls, or on the upper floors of buildings. Oriental cockroaches can tolerate cool weather, and outdoors they can be found under garbage cans, mulch, leaf brush, and other sheltered, damp areas.

Life Cycle and Seasonal History

Mated female Oriental cockroaches produce an egg capsule called an ootheca, which contains about 16 eggs. The female carries the ootheca for 12 hours to 5 days, and she deposits it near a protected area with a food source. After 6 to 12 weeks, the nymphs hatch. Nymphs look very similar to adults, but they are smaller and do not have wings. In approximately one year, the nymphs undergo seven molts before becoming adults. An adult Oriental cockroach can live from one to six months depending on the conditions. Without a food source, Oriental cockroaches can live for approximately one month if water is available. If both water and food are not available, they can live approximately two weeks.

Oriental cockroaches tend to be seasonal, and adults often appear during the spring and summer months. Oriental cockroaches can survive long periods of subfreezing weather. Mating, also called pairing, can occur anytime of the year.

Human Interaction and Urban Impact

Oriental cockroaches are pests that cause health concern. They are often found in unsanitary conditions, and feed on garbage and decaying organic matter. They can transmit various diseases that affect the human digestive system, such as diarrhea and dysentery. Bacteria, protozoa, and viruses have been found on cockroaches and in their gut. Cockroach legs and bodies spread disease-causing organisms to food, utensils, and surfaces. Oriental cockroaches also produce allergens on their bodies and in their feces, and they may be a potential cause of childhood asthma and allergic dermatitis. These cockroaches also produce a very strong, noticeable odor.

Prevention and Management Approaches

Oriental cockroach nymph

Prevent cockroaches from entering the home or building by sealing around windows and doors and by caulking cracks around pipes and other cracks on ground-level walls. Fix leaky pipes and ventilate damp areas.

Oriental cockroaches feed on garbage and decaying organic matter, so it is best to remove trash from the home in a timely manner and store it away from the building. It is also very important to use good sanitation practices in the kitchen and other areas of the home where food is prepared and served to prevent cockroach infestation. Clean spilled foods from surfaces; do not leave dirty dishes overnight; and store food in well-lidded containers. Food should be stored in containers with tight-fitting lids.

Cockroach management starts with surveying and monitoring. Sticky traps placed in strategic locations should provide some information on the extent of the infestation. Place traps against a wall, in corners and drawers, and along shelves and counters. Many commercially available traps contain baits to attract cockroaches. If monitoring reveals heavy harborage areas, baiting is an effective control method against cockroaches. Check the traps frequently and replace as necessary.

Vacuuming cockroaches using a crevice attachment may be a good option. Discard the vacuum contents after use, and it’s recommended to seal the contents in plastic bag to prevent escapes by those cockroaches that survived the vacuuming process.

The use of aerosol foggers to control cockroaches within a building is not effective. The application of aerosol foggers may disperse the cockroaches further into the structure, resulting in more difficult control. Perimeter spraying around the building may help in limiting Oriental cockroach infestation from outdoors. The goal of perimeter spraying is to create a continuous insecticidal boundary around the structure. Only use insecticides that are labeled for this type of application. If an insecticide is used to control cockroaches, always use precaution and follow the label carefully before using. Insecticides have a certain amount of toxicity to mammals; children and pets are especially at risk.