IPM for Cockroach Infestations

Integrated Pest Management (IPM) programs for urban structural pests, including cockroaches, continue to achieve increasing acceptance with pest management professionals, government agencies, schools and the public.

Many pest control companies have implemented urban IPM programs; however, they may call it by other names. For instance, "pest elimination" is a term used when guaranteeing the customer will not see cockroaches after initiating a program. Even with variable definitions of urban IPM, most industry professionals agree that it is important to diversify the methods or "tools" used for cockroach control. In many cases, multiple methods can provide the best results, delay the onset of insecticide resistance, and reduce human exposure to insecticides. One way to discuss urban IPM is to divide the strategies for cockroach control into three major categories: (1) monitoring, (2) non-chemical strategies, and (3) chemical strategies. The following article focuses solely on monitoring techniques.

MONITORING. One of the most important steps in a cockroach Integrated Pest Management program is decision-making. Home-owners and business owners look to their pest management professionals to make informed decisions about the need to apply treatments for cockroaches and, based on need, the best measures available. Monitoring is the strategy providing the information necessary to make these decisions. Key aspects of monitoring include:

• Identification

• Inspection, including use of flushing agents and monitoring traps

• Prediction

• Evaluation

• Decision

IDENTIFICATION. In the past, the term "think like a cockroach" has been used to successfully implement control of these pests. Proper identification of the infesting cockroach species is the first step in monitoring, understanding, and ultimately controlling the infestation. The previous part of this chapter provides the necessary information for pest professionals to identify and understand the biology of the major and incidental cockroach pests. In most cases, adult cockroach species are easily identified. However, professionals must not be complacent with their identifications (i.e., Asian cockroaches vs. German cockroaches).

Also, immature stages of cockroaches can be difficult to identify. American, smokybrown, oriental, and other larger species of cockroaches have early nymphal stages that may be the same size and could be mistaken for predominantly indoor species such as German or brownbanded cockroaches. In southern areas, the peridomestic species are primarily outdoor pests, so insecticide application to building interiors is usually not necessary.

INSPECTION. Cockroaches are cryptic and often go unnoticed until populations are so large the potential for contamination or possible health problems, such as allergies, becomes apparent. The premises must be inspected to properly identify all the cockroach pests and to determine the extent of the infestation. In areas where peridomestic cockroaches are present, the inspection must include a search of potential outdoor harborages and entry points. Ultimately, the food, water, and harborage essential to the survival of cockroach populations should be found. Sources of reinfestation, such as incoming goods, must be identified along with conducive conditions, such as inadequate sanitation, leaking water pipes, and excessive outdoor vegetation. In addition, any sensitive situations should be noted, such as children, pets, fish tanks, and sensitive electronic equipment, such as computers, fire alarms, etc.

Inspection for cockroaches usually involves visual inspection, often with use of a pyrethrin flushing agent to locate cockroach hiding places. Monitoring traps are frequently used to augment visual observations. A bright flashlight is a must for inspections. Use of a mirror to inspect difficult-to-see spots and a willingness to climb high and low, inside and outside, also are essential to determine the extent and location of cockroach infestations. Client cooperation is generally crucial for long-term success. Customers may also assist with the inspection and monitoring process through reporting or logging pest sightings, thus documenting the exact time and location.

Many professionals use pyrethrin aerosols, also called flushing agents, to flush cockroaches from infested machinery and other harborages. However, pyrethrins can scatter and repel cockroaches to noninfested areas, so the service professional should consider this possibility prior to using flushing agents.

Monitoring traps are highly useful tools for inspection, both indoors and outdoors. When traps were compared with other methods of surveillance, they were found to be less disruptive of cockroach populations and provided a more realistic estimate of population size for German cockroaches, and for peridomestic cockroaches. Commercially available sticky traps or rodent glue traps are the types most often used by the public and the pest control industry. Most of these sticky traps are baited with attractive food substances, while some incorporate German cockroach excreta or aggregation pheromone as an attractant. The use of traps to eliminate a German cockroach population within large structures is not realistic.

PREDICTION. After implementing monitoring strategies, including proper identification and thorough inspection, a professional should have the necessary knowledge to eliminate the cockroach infestation and predict when and where cockroach infestations may recur. The basic concept of prediction is that population levels of any pest are not constant and change through time. Seasonality or time of year usually has the greatest impact on cockroach abundance. Even with indoor cockroach species, populations may decrease during winter and will usually increase during summer when temperature and relative humidity increase. As populations grow larger, human contact with cockroaches also increases, thus providing more necessity to implement control measures. Prediction of infestation allows control measures to be applied before customers decide to change pest control companies or the home or business requires extensive treatment. Professionals should rely on their past experience and treatment records to predict when cockroach populations tend to peak in their area. Such a strategy works best with peridomestic species.

In addition to seasonal changes, building and landscape characteristics can be used to help predict cockroach population trends and movement. Experienced professionals will often have insight regarding buildings most prone to cockroach problems. Over time, patterns of activity will emerge within any building — home or business. In some situations, cockroach infestations are easy to predict due to obvious structural and sanitation issues. In other cases, however, especially with peridomestic species, inspection and predicting population trends and movement may prove more challenging. The areas in which peridomestic species harbor in and around homes may be too numerous and widespread to inspect.

Sometimes, even though pest management professionals do a good job of prediction, long-term cooperation by customers is lacking. After an initial inspection and treatment, the customer may restrict the service professional’s access to the building or areas of the building. If access to possible harborage sites is denied, the professional should communicate to the client that adequate control of the cockroach infestation cannot be assured.

Prediction is often overlooked in urban IPM programs. However, prediction of cockroach population trends and movement can eliminate the need for some treatments. Pest management professionals who not only identify current problems but also predict and intercept future problems will distinguish themselves by providing long-term results for their customers.

EVALUATION. Another important aspect of monitoring is periodic evaluation of the IPM program. Lack of timely follow-up and evaluation can result in program failure and lost customers. Prior to performing any service, the service professional should personally review the service plan with the customer and address any concerns he or she may have. After the service, a follow-up meeting to review the results and answer questions will likely enhance a customer’s peace-of-mind and confidence that the infestation has been effectively and safely controlled. In the event the customer is not satisfied, appropriate steps must be taken quickly to remedy the concern to the customer’s satisfaction. Timely and proactive communication is important in overall customer satisfaction with a cockroach control program.

Continued monitoring and inspection are particularly necessary for German cockroaches, as eggs or other stages may be reintroduced with incoming goods, personal belongings, or from neighboring areas. Apartment buildings and restaurants are two examples where continued monitoring and service are especially warranted to provide a cockroach-free environment.

DECISION. In most cases, no single tool will provide complete suppression of cockroach populations. The professional must evaluate the information and make decisions based on the pest species, the extent of the infestation, available chemical and nonchemical controls, cost effectiveness, areas to be treated, and attitudes of the customer as to which tools they will accept. Sensitive situations must also be considered, such as the presence of children, pets (including birds, fish, and reptiles), and items that may be affected by certain formulations. Sensitive sites requiring careful monitoring and minimal pesticide applications include animal rearing rooms, pet stores, zoos, schools, day-care centers, computer rooms, food areas of food-handling establishments, hospitals, nursing homes, and 24-hour supermarkets and restaurants.

The author is a senior scientist and program leader at Ecolab’s Pest Elimination Division.