Cockroaches may become pests in homes, schools, restaurants, hospitals, warehouses, offices, and virtually in any structure that has food preparation or storage areas. They contaminate food and eating utensils, occasionally damage fabric and paper products, leave stains on surfaces, and produce unpleasant odors when present in high enough numbers.
What if you fell victim to nasty roaches? First of all, don’t panic! Even if your house has many cockroaches, you CAN help keep cockroaches out of your living area with the information given in this article.
Types of Cockroaches
While there are over 3,500 species of cockroaches worldwide, there are four that are of particular concern for individuals, food service establishments and businesses. The four species of cockroaches specifically are notorious for being common pests:
- German cockroach
- Brown-banded cockroach
- Oriental cockroach
- American cockroach
Of these four species, the German cockroach has the greatest potential for becoming persistent and troublesome, followed by the brown-banded cockroach, both of which prefer indoor locations. Oriental and American cockroaches occasionally pose problems in moist, humid areas.
Cockroaches Habitat and Food
All cockroaches like warmth and moisture. They like tight places where their bodies touch the top and bottom; places like very small cracks between walls and floors, or in cabinets. You can also find them in wet wood piles, under porches, behind counters, stoves or refrigerators, in floor drains, under bathroom or kitchen sinks, in furnace rooms, behind air vents, etc.
They eat many things – food crumbs, glues, paints, garbage, soiled laundry, or soap, etc. Different kinds of cockroaches prefer different places.
American and Oriental cockroaches like warm, damp spots like basements or furnace rooms. Brown-banded cockroaches may be found anywhere, even in drawers.
German cockroaches are usually found in areas with food, warmth, and moisture such as kitchens and baths.
Harm Caused by Cockroaches
Cockroaches cause harm in five main ways:
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- Disease transmission. When cockroaches that live outdoors come into contact with human excrement in sewers or with pet droppings, they have the potential to transmit bacteria that cause food poisoning (Salmonella spp. and Shigella spp.) if they enter into structures. German cockroaches are believed to be capable of transmitting disease causing organisms such as Staphylococcus spp., Streptococcus spp., hepatitis virus, and coliform bacteria. They also have been implicated in the spread of typhoid and dysentery.
- Allergies. Indoor infestations of cockroaches are an important source of allergens and risk for asthma among some populations. The levels of cockroaches and allergens have been directly related to cockroach density, housing disrepair, and sanitary conditions.
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- Food Contamination. Cockroaches like starch and will chew on starchy types of products such as cereal, sugary substances and meat products. Also, the fecal material from feeding can contaminate food.
- Property Damage. German cockroaches will feed on books and fabrics and thereby destroying them. Their byproducts may stain surfaces.
- Psychological distress. The sight of cockroaches can cause considerable emotional distress.
Use the IPM Approach to Get Rid of Cockroaches
How do you manage cockroaches and get rid of them for good? Managing cockroaches is not easy. Some control methods take time to work. If you have a lot of cockroaches, it may take a few weeks, a month, or longer to get rid of them. The most effective method of managing an established cockroach infestation is by applying an integrated approach that utilizes several different strategies.
Integrated Pest Management (IPM) is the most effective means of controlling a cockroach infestation and preventing its re-occurrence. In other words, change the situation that promotes cockroaches! All aspects of the situation must be evaluated:
- Reduce food and water sources
- Eliminate hiding places
- Consider using baits
- Avoid sprays if possible
- Use traps to monitor the population
If you know the species of cockroach, you will be better able to determine where the source of infestation is and where to place traps, baits, or insecticides. Note locations of suspected infestations and concentrate control and preventive measures in these areas.
Chemical Control
The keys to controlling cockroaches are sanitation and exclusion: cockroaches are likely to re-invade as long as a habitat is suitable to them, that is, if food, water, and shelter are available, so the conditions that promoted the infestation must be changed.
In addition to sanitation and exclusion, baits can be effective against most species of cockroaches. Pesticide spray products are registered for use on cockroaches and may be used to immediately suppress populations, but they will not provide a long-term solution. Only altering the conditions that allowed the cockroaches to become established will provide a lasting solution. It is important to know that commercially available devices that emit ultrasound to repel cockroaches are not effective.
Insecticides are most effective in controlling cockroaches when combined with sanitation and exclusion practices that limit the cockroach’s ability to establish or reinvade; chemical control alone will not solve the problem. If insecticides are used, they must always be used with extreme care. Indoor chemical control is warranted only if the cockroach population is established, but not for an incidental intruder or two.
Baits and Bait Stations
Bait products are the primary pesticides used to treat cockroach infestations. They can be packaged as pastes, gels, granules, or dusts. Most insecticides used in baits are slow acting. Consequently an effective bait program does not give immediate results, but may take 7 days or longer to provide visual evidence of its effects.
Baits can be quite effective for long-term control of cockroaches unless the cockroaches have other food sources available to them. Baits do not control all cockroaches equally. Female cockroaches with egg cases do very little feeding and avoid open spaces; consequently they are less likely to be immediately affected by a bait.
The most popular form for home use is prefilled bait stations, which are small plastic units that contain an attractive food base along with an insecticide. Refillable bait stations are available in stores and are refilled with bait granules or gel.
The advantage of bait stations is that insecticides can be confined to a small area rather than being dispersed, and they are relatively child resistant. Baits in plastic containers also remain effective for many months.
For crack and crevice treatments, gel baits can be very effective. Apply gel using a bait gun or syringe in small dabs in cracks and crevices where cockroaches will find it. While they are fresh, bait gels are very effective when placed in locations where they will be found by cockroaches. To remain effective, however, the gels need to be reapplied frequently.
Bait gels dehydrate in about 3 days when left in open air, it is therefore recommended that gels be used indoors only. Baits that are available to homeowners can usually be purchased at most retail outlets that carry garden supplies.
Examples include Stapleton’s Magnetic Roach Food by Blue Diamond, Combat gel bait and prefilled bait stations, and Pre-Empt Professional Cockroach Gel Bait. These products may vary in effectiveness according to cockroach species.
As with sticky traps, insecticidal baits do not attract cockroaches so place them near hiding spaces or where roaches are likely to encounter them when foraging. If the bait stations are labeled for outdoor use, place them around building perimeters, in valve or water meter boxes, and around planters.
Indoors, place bait packets under or behind appliances, along wall borders, and in cabinets. Baits can also be placed next to fecal specks and droppings of cockroaches, which contain a natural attractant or aggregation pheromone. Look for these fecal specks and droppings under kitchen counters, behind kitchen drawers, and in the back of cabinets.
Insecticidal dusts can be an important part of an IPM program when applied in enclosed, out of the way locations where cockroaches hide. The most common active ingredient is boric acid powder. Boric acid powder is a contact poison and can be used preventively or when treating existing infestations. Boric acid powder is the least repellent of all the insecticides for cockroach control, and if it remains dry and undisturbed, it provides control for a very long time.
Formulated as an insecticide, boric acid dusts usually contain about 1% of an additive that prevents the powder from caking and improves dusting properties. If it gets wet and then dries and cakes, it loses its electrostatic charge and will not be picked up readily by the cockroach. If this occurs, reapply powder to these areas.
Because it has a positive electrostatic charge, the dust clings to the body of a cockroach as it walks through a treated area and the cockroach ingests small amounts when it grooms itself. Since, boric acid powder is fairly slow acting, it may take 7 days or more to have a significant effect on a cockroach population.
Due to its toxicity to plants, boric acid is not recommended for outdoor use.
Blow dust into cracks and crevices or lightly spread it in areas where visible residues are not a problem and where people will not contact it. Remove kick panels on refrigerators and stoves and apply a light film of dust throughout the entire area underneath these appliances.
A very thin film of dust is more effective than a thick layer. Holes that are the same size as the tip of a puff-type applicator can be drilled into the top of kick panels beneath cabinets and powder may be applied through the holes to these areas as well as under the sink, in the dead space between the sink and wall, and around utility pipes. Also treat along the back edges and in corners of shelves in cabinets, cupboards, pantries, and closets.
Sprays and Aerosols. Although sprays may provide a quick, temporary knockdown of cockroaches, they do not give long-term control. Sprays are often highly repellent to cockroaches and should not be applied to surfaces in areas where traps or bait stations are located.
Sprays may also disperse cockroaches to other areas of the building from which they could later return. Also, cockroaches have become resistant to many insecticides that formerly controlled them.
Sprays should not be necessary if an IPM program using sanitation, exclusion, and appropriate baits and dusts is practiced. However, in heavily infested structures, an initial application may be necessary to quickly reduce excessive numbers of the cockroaches while structural modifications are being initiated.
Follow-Up
When cockroach populations are under control, continue monitoring with traps on a regular basis to make sure re-infestation is not taking place. Maintain sanitation and exclusion techniques to avoid encouraging a new infestation.
If severe re-infestations of household cockroaches continue to recur, consider that they may be coming in with items such as cardboard boxes. If you suspect cockroaches enter with groceries brought into the home, stop patronizing that market.
Frequently they will enter from neighboring apartments if you live in a multiple family dwelling. To report a cockroach infestation call local Department of Public Health.
References:
Michigan Department of Agriculture and Rural Development, Questions and Answers about Cockroaches, http://www.michigan.gov/mdard Effective Management Of Cockroach Infestations, County of Los Angeles · Department of Public Health Vector Management Program