American, Australian, and smokybrown cockroach adults are of similar shape and appearance. They range from 1 1/4 to 1 1/2 inches long with American and Australian cockroaches averaging slightly larger than smokybrowns. Smokybrown adults are uniformly dark reddish brown to nearly black in coloration. The head shield (also called the pronotum), which is the body region right behind the head, is a solid dark color. The wings of smokybrowns cover the abdomen. American cockroach adults are brown to reddish brown with a cream-colored border on the head shield. The wings of male American cockroaches extend slightly beyond the abdomen, while the wings of females are about the same length of the abdomen. Australian cockroaches have a dark "Batman" pattern on the head shield; have a light, comma-shaped bar on the front edge of each wing; and the wings cover the abdomen. The Oriental cockroach is approximately 1 inch in length and dark brown to black. The wings of male Oriental cockroaches do not extent to the tip of the abdomen leaving the last 1/4 of the abdomen exposed. Adult female Oriental cockroaches do not have developed wings and only differ in appearance from large nymphs by having venation on the wing stubs. The Turkestan cockroach is about 1 inch in length. Adult males have wings that cover the abdomen and are yellowish tan in color. Adult females have short, rounded wings with creamy stripes along the edges and a pear-shaped
body. Each of these cockroaches deposit purse-like egg cases.
The species listed above are the most frequently seen cockroaches in urban areas of the United States. They are primarily outdoor cockroaches and prefer warmer climates and moist surroundings. The American cockroach is common in city sewers and basements, particularly around pipes and drains. The smokybrown prefers tree holes, loose bark, and mulch. The Australian cockroach is abundant outdoors and in greenhouses. The Oriental cockroach is common outdoors and lives in warm, damp shady areas near the ground or any area containing natural debris. The Turkestan cockroach is a detritus feeder, is often found in meter and irrigation boxes and exposed compost piles, and the males are attracted to lights. Each species can build large populations if uncontrolled and can spread bacteria by contact. Finding them inside often indicates a need to pest-proof external entryways.
Effective management includes cultural and mechanical practices such as eliminating food and water sources and harborage sites for cockroaches. Examples include removing incoming food products from cardboard shipping containers as soon as they are delivered; cleaning drains regularly; repairing leaking pipes and faucets; sealing exterior cracks and crevices; sealing cracks and crevices in food storage, preparation, and serving areas; and sealing openings around the edges of electrical boxes, bulletin boards, and signage. Due to the development of effective insecticide bait formulations, cockroach problems have become much less prevalent in general. Spray-applied residual insecticides are much less effective than baits in reducing cockroach populations and increase potential for exposure. Enzyme-based cleaners can also be effective in cleaning up cockroach debris.
One cockroach justifies monitoring, and more than one justifies baiting. More than 10 justifies an inspection to find out how they are entering the structure, find areas that are not up to sanitation standards, and locate other conducive conditions. Keep in mind that each egg case may contain 14 to 24 eggs, so the threshold may vary by life stage observed.
Cockroaches are primarily nocturnal and are usually active at night and hiding in harborages during the day. They are thigmotactic, preferring to harbor in locations where they have surface contact on both upper and lower body surfaces. This is why they prefer places such as the flaps of cardboard boxes and the space between wall-mounted fixtures and the wall. These are key locations for visual observation for cockroaches, egg cases, and feces. Feces may be wet or dry depending on the environment. In humid environments, these cockroaches will leave smears of fecal material. In drier environments, they will leave fecal pellets.
Inspection practices should include checking for unsealed openings such as missing or loose pipe and conduit escutcheons, unsealed edges around sinks and cabinets, unsealed edges of bulletin boards or wall-mounted electrical panels, mirrors, light fixtures, fire alarms, or emergency lighting. Inspections should focus on areas where food and water are present, including food storage areas, kitchens, food serving lines, cafeterias, locker rooms, concession stands, and staff lounges.
The cockroaches are primarily outdoor cockroaches, so exclusion and sanitation are the primary defenses against these pests. Prompt clean up of spills, proper food storage and waste handling, preventing access to water by fixing plumbing leaks, eliminating harborage and access to the building by sealing cracks and crevices, removing products from cardboard shipping containers before shelving, and inspecting incoming products and rejecting any containing cockroaches, cockroach droppings, or egg cases can all be effective tools in preventing cockroach establishment. Clean up any areas not up to sanitation standards. Remove cardboard and other debris that could serve as shelter. Seal sinks and cracks to remove access to harborage. Ensure no gaps under exit doors.
Insecticide bait formulations have been developed that are effective on cockroaches. Chemical management options that reduce potential for exposure include insecticide baits in premanufactured, enclosed bait stations or gel or liquid baits placed in cracks and crevices. Bait stations may be used in areas not accessible to children. Use other bait formulations in inaccessible areas where cockroaches may hide.
Use boric acid and silica gel in dry inaccessible voids, cracks, and crevices. Be careful when applying dusts as they may move with air intake or air movement from motors.
Spray-applied residual insecticides can be used around known harborage areas, preferably outdoors or in areas away from human occupancy. Use these pesticides with care around areas where children have access. They should be used only as needed and only in targeted areas.
Always read and follow the label on the pesticide container. The label is the law. Pesticides must be used in accordance with federal, state, and local regulations. Applicators must have proper credentialing to apply pesticides and should always wear all personal protective equipment (PPE) that is specified on the pesticide label. All labels and Material Safety Data Sheets (MSDS) for the pesticide products authorized for use in the IPM program should be maintained on file. Check with your school district for notification and posting policies.
After the initial monitoring to pinpoint sites of infestation, treatment efforts should be concentrated at these locations. A week or two after treatment, monitors should again be placed at the infestation sites to see how well the treatment efforts are working. Place fresh traps at the locations indicated on your map and count the number of cockroaches in the traps after 24 hours. If the trap catch has dropped considerably, the cockroach population has declined and progress has been made. If not, another treatment strategy should be considered and greater efforts must be made to eliminate food, water, and harborage resources.To assess the continued success of treatments and detect any new infestations, continue to monitor after the IPM program is underway. Vigilance is important and good record keeping will save time and energy.
Authors: Compiled from publications by Godfrey Nalyanya, Lawrence “Fudd” Graham, Janet Hurley, S. Darr, T. Drlik, H. Olkowski, and W. Olkowski, PMSP