Oriental Cockroach

HYG-2097-97

The Oriental cockroach known as the "water bug," is more closely associated with damp areas than the other common roaches. These insects feed on garbage and decaying organic matter and are often considered the filthiest of the house-infesting roaches. They are found in damp basements, cellars, crawl spaces, near drains, leaky water pipes and beneath refrigerators, sinks and washing machines, under floors, and inside walls. They forage mostly on first floors of buildings. Outdoors, they are found beneath decomposing leaves or stones in mulching materials, in trash and at municipal sewer plants. During the autumn, there can be a mass movement into buildings, but because of their preference for cooler temperatures, can be found outdoors and in unheated buildings during the winter. Roaches can foul food and produce an unpleasant odor. Some homeowners are allergic to roaches, and the pests can contaminate food with certain bacterial diseases that result in food poisoning, dysentery or diarrhea. Cockroaches can cause childhood asthma.

Identification

Most cockroaches have a flattened oval shape, spiny legs and grow long, filamentous antennae. Adult Oriental cockroaches are shiny, dark brown or black, about 1 to 1-1/4-inch long and have nonfunctional wings incapable of flight. Females are about 1-1/4-inch long, broad and have only little pads for wings. Males are about one inch long, more slender and have wings not reaching the tip of the abdomen. Immature roaches (nymphs) are darker in color than adults, similarly shaped and wingless. Egg cases are dark reddish-brown, one inch long (largest of the common roaches), and appear slightly inflated.

Life Cycle and Habits

Oriental cockroach females (more numerous than males) carry the egg capsule 12 hours to 5 days and deposit them in a sheltered location near or within a food supply at a warm, sheltered spot. Females produce 1 to 18 capsules, each containing up to 16 eggs. Eggs hatch in about 60 days and nymphs develop in about one year. Adult females live 1 to 6 months. These roaches, most common during May, June and July, are more sluggish than the other common roaches, developing in damp basements and sewers and foraging mostly at or below ground level structures. They are usually not found in cupboards, on walls or on upper levels of buildings. They occur outside during warm weather, and, during cool periods, may migrate in masses indoors. They have a preference for high-moisture conditions. They can live without food for a month if water is present, but die in two weeks without food and water.

Control Measures

Integrated Pest Management (IPM)

Integrated Pest Management (IPM) is a systems approach that combines preventive techniques, non-chemical pest control methods and the wise use of pesticides with preference for products that are least harmful to human health and the environment. It is not the total elimination of pesticides but an alternate approach to traditional pest control measures. Complete reliance, in the past, on pesticides alone for pest control allowed certain pests to develop resistance, created potential human exposure to harmful chemicals, produced unsound environmental contamination, and created a threat to nontarget species and pesticide waste. IPM consists of routine inspection and monitoring with treatment only when pests are actually present, thus reducing traditional, routine pesticide application treatment (calendar date sprays) whether pests were present or not.

By following a cockroach IPM plan, cockroach activity is monitored using sticky traps or glue boards. These monitoring stations are placed throughout a structure where roaches are likely to be found such as in dark places along cabinets, walls, under appliances, on pipes, etc., in bathrooms and kitchens. Any tight cracks about 3/8 inch or smaller are good cockroach habitats. Monitoring indicates whether roaches are present and if control practices are working. IPM tools include glue boards, baits, vacuum cleaners, caulking, insect growth regulators (IGRs), etc.

Detection

Oriental cockroaches can be detected by examining the premises after dark with a flashlight. During the day, probing hiding places with a wire or thin wood strip will expose roaches. Adults and nymphs usually hide clustered together. Household sprays of pyrethrins applied to hiding places will flush out roaches, sometimes killing them if they contact the spray.

Prevention and Sanitation

Oriental roaches can move from one building to the next during the summer, entering through cracks in foundations, around loose-fitting doors or windows, and along water and gas pipes. Repair leaky water faucets and pipes. Seal openings such as cracks in foundation walls, exterior walls around air conditioners, doors, windows, floors, ceilings, around plumbing fixtures, electrical outlets, baseboards, etc. with putty, plastic wood or other caulking material. Inspect for roaches and their egg cases in sacks, cartons, boxes, used appliances and furniture, etc., brought into the home. Sanitation is critical in roach control. (Unclean living conditions from housekeeping neglect is the major contributing factor of roach outbreaks.) Clean areas beneath cabinets, sinks, stoves, refrigerators, etc. as well as cupboards, pantry shelves and food storage bins. Clean up spilled foods and liquids. Avoid leaving scraps of food on unwashed dishes and countertops overnight. Keep food in tightly sealed containers, rinse cans and bottles before putting in the trash, and transfer garbage outdoors into roach-proof receptacles away from the house. Leftover pet food should not remain in the feeding dish overnight.

Insecticides

Apply chemicals at roach hiding places. Enter a dark room quietly, turn on the light and watch where the roaches run. Spot treat these hiding places and known pathways, especially under and behind loose baseboard or molding strips and around pipes or conduits along the walls and through it. Do not treat entire floors, walls or ceilings. Roaches may hide around the kitchen sink or drain board, in cracks underneath cupboard, and cabinets. Surfaces where food is prepared should not be treated. Roaches in buildings with multiple dwellings usually require the treatment of other units as well. Since they often move into dwellings in large populations, a barrier treatment around the building and the foundation should be applied.

There are numerous cockroach insecticide formulations. Some are labeled "general use" for homeowner application, and others are labeled "restricted use" for professional pest control or licensed, certified pesticide applicators only. Before using any insecticide always read the label and follow directions and safety precautions.

Dusts such as bendiocarb (Ficam D), boric acid powder, pyrethrins (Drione) or silica aerogel (Dri-Die) can be applied with a puff duster into hiding places normally hard to reach with a spray.

Sprays, either oil-based or water emulsion, are applied as spot or crack and crevice treatments. These include propoxur, acephate, chlorpyrifos, diazinon, permethrin or resmethrin. Only the licensed certified pest control applicator may apply bendioarb, propetamphos, trichlorfon, cyfluthrin, cypermethrin, deltamethrin, esfenvalerate, lambda-cyhalothrin, tralomethrin and bifenthrin. Insect growth regulators or IGRs include hydroprene (Gentrol) and pyriproxyfen (Archer, Nylar) which act on immature growth stages by contact or ingestion, disrupting molting and development to fertile adults. (A combination of an IGR followed up by use of a bait is often effective.) Some still use contact insecticides in mist or ULV (ultra-low volume) machines to treat the entire indoor area. Open all drawers and closet doors so roach hiding places can best be treated. However, the trend is toward less sprays and aerosols and more IGRs and baits.

Baits

Certain segments of the public may prefer baits to sprays such as schools, hospitals, office buildings, etc. Baits include pastes, gels, particle baits and bait stations.

Bait advantages: low hazard (toxicity) to people; suited for sensitive accounts; IPM oriented; offer effective control. Disadvantages: high bait cost; precise placement required; not cost effective in heavy roach infestations.

Sticky traps have openings at both ends with the inside surface covered with a very sticky adhesive and slow-release food attractant. Properly placed traps, to and from roach hiding and feeding areas, can catch numerous adults and nymphs daily, especially brownbanded and German cockroaches. Traps are best used along with preventive and insecticidal applications to monitor populations. Trapping can determine haborage areas and infestation severity, monitor effectiveness of pesticide applications, and detect any roach population increases that may require additional pesticide treatments.

Fumigation is seldom used but will clean out a cockroach infestation. It must be applied only by a licensed, certified pesticide applicator.

If a severe cockroach infestation develops or if you are in doubt as to the control measures to use, contact a reputable, licensed pest control firm who has the chemicals, training and experience to do a thorough job.

This publication contains pesticide recommendations that are subject to change at any time. These recommendations are provided only as a guide. It is always the pesticide applicator's responsibility, by law, to read and follow all current label directions for the specific pesticide being used. Due to constantly changing labels and product registration, some of the recommendations given in this writing may no longer be legal by the time you read them. If any information in these recommendations disagrees with the label, the recommendation must be disregarded. No endorsement is intended for products mentioned, nor is criticism meant for products not mentioned. The author, The Ohio State University and Ohio State University Extension assume no liability resulting from the use of these recommendations.