Cockroaches are one of the oldest groups of insects, indicating how successful they have been in adapting to changes in their environments. One reason for this success may be related to diet--they are scavengers and will eat anything organic. They prefer food sources such as starches, sweets, grease and meat products, but other items may include cheese, beer, leather, glue, hair, starch in book bindings, flakes of dried skin or decaying organic matter (plant or animal).

Cockroaches are attracted to warm, moist environments. They spend the daylight hours in dark, secluded sites under refrigerators, stoves, false bottoms in kitchen cabinets, in the backs of cabinets and in crevices between baseboards and floors or cabinets and walls. They may also be found behind pictures or within electronic equipment. A number of these openings will ultimately lead to voids in the stud walls. The insects leave these sites at night to forage for food and water. The presence of cockroaches during the day may indicate a large population.

There are about 3,000 species of cockroaches in the world and about 50 occur in the United States. Of these 50 species, the three most common in the Northeast are the German cockroach, the American cockroach and the brownbanded cockroach.

German Cockroach: Blattella germanica

The German cockroach is 12 to 17 mm (1/2 to 5/8 inch) long, tan to light brown, and has two dark brown stripes on the body region (pronotal shield) just behind the head. Females will produce four to eight egg capsules during their lifetime, with each capsule containing approximately 40 eggs. The egg capsule is retained by the female until the eggs are ready to hatch, usually in 28 to 30 days.

German cockroaches are widespread and can be found in homes, restaurants, hospitals, nursing homes or apartments. Within these areas, the cockroaches prefer sites close to moisture and food, making them common pests in kitchens, bathrooms and food-storage areas. Of the cockroaches which infest structures, the German cockroach is probably found more frequently than other species.

American Cockroach: Periplaneta americana

The American cockroach is one of the largest cockroaches in the Northeast. It is about 40 mm (1.5 inches) long with a reddish-brown body. The center portion of the pronotal shield is light brown, while the outer edges are yellow. Even though both sexes are winged, their flight is more of a gliding movement from point to point than active flight.

The female American cockroach will not retain the egg capsule for more than a day after its formation, instead dropping the capsule in some suitable site. Under some conditions it may be glued to a surface. The number of capsules produced by a female will range from 6 to 14, with each capsule containing 14 to 16 eggs. The eggs hatch in 50 to 55 days.

The American cockroach prefers dark, moist sites where it feeds on decaying organic matter. Such sites include basements, kitchens, clothes hampers, drains, bathroom plumbing or sewers. High populations have been known to develop in sewers, from where they infest households or other structures.

Brownbanded Cockroach: Supella longipalpa

The brownbanded cockroach is 12 mm (1/2 inch) long, light brown, and has two lighter colored bands running across the body. These bands are located at the base of the wings and on the abdomen. The bands are much darker during the immature stages. The brownbanded female carries the egg capsule for 24 to 48 hours before gluing it to a surface. The capsule contains approximately 18 eggs that hatch in 50-74 days. An adult female produces about 18 egg capsules over a life-span of 10 months.

The brownbanded cockroach requires less moisture than other cockroaches. It is more prevalent in homes, apartments, hotels and hospital rooms than in restaurants or stores. Evidence of this cockroach may be found behind pictures, in furniture, the underside of chairs and tables, upper kitchen cabinets or the upper shelves of closets and pantries. The brownbanded cockroach often infests electrical appliances such as radios, televisions, telephones and computers.

Cockroach Control:

Identification:

Identification of the infesting cockroach is crucial to successful management. Knowledge of the preferences and habitats of each species will help to provide more accurate and effective control.

Sanitation:

Anything that can be done to eliminate the sources of food and water for the cockroaches from the home environment will help in their control:

• Do not allow dirty dishes to accumulate in the sink and remain there overnight.
• Keep food scraps in the refrigerator or in containers with tight-fitting lids.
• If pets are in the home, keep the pet food in tightly sealed containers, and do not allow food to remain in the bowls overnight. Feed only what the animal will eat at the time of feeding.
• Remove garbage from the home on a routine basis. Keep outside containers covered, especially at night.
• Periodically check and clean the evaporation pan under the refrigerator or freezer.
• A critical point may be the area between the stove and cabinet, where grease and food scraps often accumulate. Pull the stove out periodically and clean thoroughly.

Cockroach traps are containers (available in various shapes) open on both ends and with adhesive surfaces on the inside. The traps may or may not include a food attractant. As the cockroach enters the box, it becomes trapped in the adhesive. Proper placement is essential! Cockroaches move from point to point along lines where vertical and horizontal planes meet. This may be where the floor and wall join, it may be where the bottom of a drawer meets the side of the drawe, or where a shelf joins the wall of a cabinet. Place traps flush to the wall, as even a small gap between the trap and wall allows the cockroach to bypass the trap.

In single-family homes in the Northeast, sanitation should be adequate to eliminate and prevent cockroach infestations. If the above control options are not sufficient, several treatment methods are available, including baits, insecticides and dusts.

Baits:

Cockroach baits contain an insecticide (or pathogen) plus an ingredient to attract the cockroach. Baits are packaged as easy-to-use containers which are placed in areas of known cockroach activity. Insecticides available as baits are hydramethylnon (Combat), sulfluramid (Raid Max) and avermectin (Roach Ender).

Insecticides:

Insecticides give the best control when applied under objects (refrigerators and stoves), along lines where shelving meets walls (top and bottom), in the backs of the cabinets, behind pictures (depending on species) and as crack and crevice treatments. Remove dishes, cookware and foods from cabinets before treatments; return after the spray has dried. There are many products readily available for this purpose.

Dusts: These compounds are harder to use but give long-lasting control. Boric acid is the only available material in this category. It should be applied to cracks, crevices and wall voids as well as under stoves, refrigerators and in the backs of cabinets. It should be applied as a thin film--do not apply in piles or a thick coat.

Adapted from Dr. James H. Jarratt, Mississippi State University Extension Servic, 1999.
Photos from the Clemson University Extension.