[Annual Cockroach Control Issue] Controlling Cockroaches

In the past several years a lot has been made of the fact German cockroaches don’t seem to be the problem they once were, especially in commercial situations. Gel cockroach baits have worked extremely well for the control of Blatella germanica, yet in the past couple of months, articles have appeared detailing the behavioral avoidance of gel baits by this species.

Although it is true cockroaches are less of a concern today than they have been, these pests are still readily present and easily found. Pest control companies may very well be receiving just as many calls, statistically, to control cockroaches as they have been in the past. What has changed is the fact that, with the German cockroach at least, calls for repeat services are dramatically reduced because the infestations are more readily controlled on the initial services. One can still go into many restaurants and find German cockroaches, as well as encounter this pest in multifamily housing.

Usually lost in the midst of all the discussion regarding the German cockroach is the occurrences of other cockroach species, in particular American, oriental and smokybrown cockroaches. Especially in southern states, the larger cockroach species prompt customer requests for service. Most such calls originate from homeowners whose houses often provide ideal living conditions outside where such cockroaches may thrive. Additionally, it is more difficult for the average customer to overlook the 1½- to 2-inch Periplaneta species as opposed to seeing an occasional ½- inch German cockroach. The sighting of more than one large cockroach in a short period prompts loud cries to "get rid of those bugs."

The basic principles of cockroach control are basically the same for residential and commercial situations. In a sentence, elimination of cockroach infestations requires investigating all potential harborages in order to find and treat all active harborages. The types and locations of potential harborages changes with the species involved, type of building and the conditions present at the time. The knowledge and skill of the professional comes into play in his or her ability to quickly recognize potential harborages and to determine any activity. Each site of activity must then be treated accordingly based on which treatment technique and formulation is best suited for that specific microenvironment.

RESIDENTIAL ROACH MANAGEMENT. In general, elimination of a cockroach infestation from a home is easier than for a restaurant, although exceptions occur. Aside from the occasional "home from Hell" infestation, German cockroaches tend to be more easily controlled than larger cockroach species. One must first start with the species involved and use its biology and habits to determine the most likely harborages. Once found, any active harborages can then be treated.

Minor German cockroach infestations are relatively straightforward. The insects will typically be confined near sources of moisture, usually the kitchen and bathrooms, although nightstands in bedrooms and utility rooms can be involved. Such infestations can be controlled by application of baits into or near active harborages and crack and void treatments where insects are found living. Inspections of other rooms can be completed, but more often, such checks will reveal pests other than cockroaches, such as spiders.

Moderate to severe German cockroach infestations pose greater obstacles. The larger the population, the more likely cockroaches will be pushed into less-preferred harborages, thus making them more difficult to locate. In such cases, it is not uncommon for the need to turn over and inspect all furniture in a room, to partially disassemble appliances to access roaches and to drill and treat wall voids.

In one case involving a severely infested vacant duplex home where new products were being field tested, more than one hour spent applying an aerosol cockroach bait by crack and crevice application failed to noticeably impact the cockroach population. Hundreds of German cockroaches lay dead in the home seven days later yet far more remained alive. A pyrethroid dust product was then applied into all visible cracks in the infested rooms. A week passed and yet hundreds of German cockroaches still lived, running about while thousands of their brethren lie dead throughout the building. The wall voids in the kitchen and bathrooms were then drilled and treated through the back of cabinets and vanities, then treated with the same dust product used the week before. Only then was the population controlled to the point where activity ceased.

In this case, as I have found in others involving severe infestations in homes and apartments, treatment of wall voids in kitchens and bathrooms is important in achieving elimination. To ignore a key active harborage, such as walls where plumbing exists, provides a source for constant reinvasion. Subsequently, service professionals often blame the products they use when the real issue was overlooking key active harborages.

ANOTHER EXAMPLE. In another case in Houston, Texas, I became involved in a bizarre residential German cockroach infestation where the house had once been fumigated yet the infestation persisted months later. The woman residing there maintained a clean and orderly home. Cracks and voids had been treated previously by conscientious service professionals including drilling and dusting every wall void in the home. Despite such Herculean efforts, however, sticky traps captured several dozen new German cockroaches a week. When I became involved, I was field testing Gencor (hydroprene) and I applied this IGR in the home and monitored the situation over the course of several months until I left the company where I worked at the time. I had gotten to be friends with the homeowner and over the course of the next two years would visit with her when back in town. I found to my delight that after about seven to eight months, her activity dropped to near zero due to the IGR application. The monitoring traps were filled with twisted-winged adults and few nymphs, a good indication of the effects of hydroprene on a dwindling population.

Few homeowners will prove as patient as the woman in the above case. Looking back, I had wondered to myself if the cockroaches were actually breeding beneath the slab, possibly where the soil had fallen away. Such an event is not uncommon with American or oriental cockroaches but would be highly unusual for the German cockroach.

Larger cockroach species are more problematic and professionals many times fail to successfully solve the problem because they focus on where the cockroaches are seen not where they are likely living and breeding. For example, in the South, if one wants to solve a smokybrown cockroach problem, he or she should focus investigative efforts on the outside and in the attic and crawlspace (if present). Research has shown the sources of this and other peridomestic species are associated with tree holes, woodpiles, mulch beds and the soffits of homes. Attics with poor ventilation tend to harbor such species as well.

Research in Florida has shown perido-mestic cockroaches, such as the American and smokybrown, are best controlled using baits with limited residual treatments applied directly into cracks and voids where such species might be found. Granular insect baits work well when applied where the insects can find them. Where failures occur, they are often the result of overlooking one or more active harborages, for example, an enclosed porch void, porch columns or an enclosed breezeway. Service and possible baiting/treatment need to extend to all edges of the property around the home because reduction of the population on the property reduces the chances of home invasion.

COMMERCIAL ROACH MANAGEMENT. Any room where food may be prepared, packaged, or served is subject to cockroach infestations. Because such environments require continued shipments of incoming goods, new cockroaches can be — and are — reintroduced more frequently than generally occurs in a home. Still, any structure can experience infestations other than food-prep facilities including schools, offices, warehouses and storerooms. The German cockroach is the primary culprit in food service, but larger species, such as the American and oriental, can plague warehouses, schools, offices and food-processing facilities.

Despite the type of cockroach and facility involved, the recipe for success remains the same — find all the active harborages and treat them appropriately. This is easier said than done in many situations due to the size and complexity of the building that may be involved.

German Cockroaches. A key factor in success against the German cockroach in food-prep/service areas is physical removal through vacuuming. Vacuums permit immediate, noticeable reduction of the population. HEPA filter-equipped vacuums need to be used.

Second, voids need to be addressed, especially those where plumbing voids exist. Conduit boxes and false ceilings also require inspection as do appliances and other machinery. Bait application and residual treatment of cracks is highly beneficial in controlling remaining cockroaches missed by other techniques. The use of an IGR is instrumental in assisting with future reintroductions of roaches.

First, a service professional must be an investigator to be successful in solving German cockroach infestations. Inspection involves observation and recognition of likely harborages. Investigation means digging in, looking deeper, analyzing the situation. Here’s an example:

• A service professional is called upon to solve a German cockroach infestation in the server station of a country club. Although a few cockroaches are found in the cabinetry associated with the area, the professional decides the large cooler is the likely source of the problem. He quickly discovers cockroaches living inside a rag hung up on a rod behind the cooler followed by dozens of cockroaches living among old posters stored between the cooler and the wall. Digging further, he removes the front panel to the motor housing and finds a long-standing infestation associated with a manila folder tucked underneath the machine (see Figure 1 on page 76). By removing and disposing of all these infested items after vacuuming the cockroaches, he baited the underneath of the machine and treated cracks behind the baseboard using a dust product.

In the same building, cockroaches were being seen in the men’s locker room. None could be found living under counters, in the stalls or the lockers. Cursory inspection of a closet revealed no activity but a drain line extended horizontally from the wall about 9 feet above the floor in the closet. On and around this pipe, he found several adult cockroaches and a considerable size fecal smear. On the other side of the wall (in the locker room by the stalls) above the false ceiling was extensive fecal smears and numerous insects. Still, he reasoned that the area was not conducive to cockroaches because it was so dry. So why were they there? Below this area was an access panel in the wall, inside which one could observe and access a vertical drain line (see Figure 2 above right). The insulation around the pipe was wet and smelled of feces. The drain line ran from a rest room on the floor above and had a small leak providing the cockroaches more than enough food and moisture to survive.

Both of these cases show why "investigation" is a more appropriate term for the primary task performed by pest professionals. Had the professional simply treated or baited around the cooler in the first example or just above the ceiling in the second, he would have failed to gain satisfactory control. That little extra effort to examine all potential harborages paid off. In going a bit further, he avoided a call-back for extra service.

Another example demonstrates a key lesson for pest professionals working with the German cockroach. A hotel began complaining of cockroaches being seen in the main banquet room during banquets, wedding receptions and similar events. Repeated (weekly) visits were proving unsuccessful in satisfying the hotel management. The service professional and his service manager dutifully visited numerous times and treated every available crack, drilled and dusted wall voids and baited the tables set up in the banquet room. Yet, they never saw one cockroach while every time a banquet occurred, cockroaches were seen on the tables.

By the time I got involved, both the food and beverage manager and the service professional were at wit’s end. I went to the room and took a quick look around. Having learned a lesson long ago when I was a service technician myself, I asked one simple question of the food and beverage manager, "What is on these tables when you have a banquet?"

The tables were bereft of any items and I knew when I participated in any banquet that the tables had skirts and they were often elaborately decorated. The manager showed me where such items were stored and the cockroaches were found living behind the edge of the large mirrors that were placed on the tables and upon which the food would be placed. The cockroaches were carried from the storeroom out to the tables several times and the hotel staff was nice enough to bring the food to them!

When a customer tells you they are seeing cockroaches, they almost always are seeing insects. Now, they may exaggerate about the numbers seen or the extent of the problem, but the pests are there and waiting to be found. In my experience, when cockroaches are seen in an area and none can be found, one needs to ask, "Is there anything that is not here now but might have been when the cockroaches are seen?" A good example is carts, but also items moved out of the area in preparation for pest control services, such as appliances, boxes, etc., could be harboring the infestation.

Large Species. It is important to remember American and oriental cockroaches prefer to breed in dark, very damp or wet areas. Oriental cockroaches can tolerate cooler environments than Americans. It is generally counterproductive to spend time inspecting and investigating in the areas where these insects are seen or are captured on traps.

An important person to speak with regarding infestations of these pests is the maintenance engineer or technician. He or she can tell you where the closest boiler room, pipe chase, crawlspace, basement, sump pump, exterior wall, etc., to the area where the insects are being seen is located. These potential harborages/breeding sites need to be investigated. Once found, the cockroaches can often be controlled by baiting only or through a combination of crack and crevice and void treatments and baiting.

In one case involving a hospital in Texas, I traced an American cockroach infestation outside to sewer manhole near the building. Hundreds of cockroaches in the manhole were treated directly with a pyrethrin aerosol. Once this population had been decimated, inside invasions ceased. The service professional was then instructed to check the manhole at least once per month and treat any cockroaches found using a contact insecticide.

In another case involving a warehouse, oriental cockroaches were ultimately traced to a harborage beneath the slab. The soil had fallen away from the bottom of the slab in one area of the warehouse and the cockroaches would enter the room above through expansion joints. The slab was drilled and treated with a dust product to control the problem. Temporary rubber corks were placed in drill holes to permit repeat applications when necessary.

In the South, American, smokybrown and Australian cockroaches often invade from outside. Breeding sites are usually associated with trees and the landscaping although some buildings may be storing lumber, pallets, boxes, or other items in which the pests might hide. In general, treatment using a granular insect bait applied into harborages reduces the population enough to minimize interior sightings. Good exclusion and sanitary practices, however, are also important components.

SUMMARY. Cockroach control in residential vs. commercial situations is similar but differs in scale. In general, considerably more time needs to be spent for commercial cockroach control, although certain residential infestations can prove taxing. The key is finding the active harborages and a professional’s knowledge, experience and persistence are critical skills for success.

The author is manager of technical services, Terminix International, Memphis, Tenn. He can be reached at shedges@pctonline.com.