Managing cockroaches is not easy. You must first determine where the roaches are located. The more hiding places you locate and manage, the more successful your control program will be. Remember that cockroaches are tropical and most like warm hiding places with access to water. Some locations may be difficult to get to. Reduction of food and water sources and hiding places is essential. If cockroaches have access to food, baits (which are a primary control tool) have limited effect. Sprays alone will not eliminate cockroaches. An IPM approach that integrates several strategies is usually required.
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. The keys to controlling cockroaches are sanitation and exclusion: cockroaches are likely to reinvade as long as a habitat is suitable to them (i.e., 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 temporarily suppress populations, but they usually do not provide long-term solutions and are not generally recommended. Commercially available devices that emit ultrasound to repel cockroaches are not effective.
Traps : Traps offer the best way to monitor cockroach populations. By placing traps in several locations and inspecting them regularly, you can identify the areas of most severe infestation and know where to concentrate control efforts. Traps also can be very helpful in evaluating the effectiveness of control strategies. Available retail cockroach sticky traps work well. These traps are open-ended and are lined inside with a sticky material.
To be effective, traps must be placed where cockroaches are likely to encounter them when foraging. The best places are at the junctions of floors and walls and close to sites where cockroaches are suspected; good potential monitoring sites can be determined by accumulations of fecal matter (e.g., dark spots or smears), cast skins, egg cases, and live or dead cockroaches. Place traps in all corners of the room to give you an idea where roaches are entering. In the kitchen put traps against walls behind the stove and the refrigerator and in cabinets. Number the traps so you can keep records for each trap separately. Check the traps daily for several days until it is apparent where the greatest number of roaches are caught; usually this is within the first 24 hours of placing a trap-after that cockroaches may become wary of the trap. Discard sticky traps by placing them in a sealed plastic bag in the trash. Keep records of roaches trapped in different locations before and after you initiate a management program to evaluate its success.
Cockroaches thrive where food and water are available to them. Even tiny amounts of crumbs or liquids caught between cracks provide a food source. Important sanitation measures include the following:
During the day cockroaches hide around water heaters, in cupboard cracks, stoves, crawl spaces, outdoor vegetation, and many other dark locations. They invade kitchens and other areas at night. Limiting hiding areas or avenues of access to living areas is an essential part of an effective management strategy. False-bottom cupboards, hollow walls, and similar areas are common cockroach refuges. Prevent access to the inside of buildings through cracks, conduits, under doors, or through other structural flaws. If it is not practical to remedy these problem areas, treat them with boric acid powder insecticides formulated for cockroach control.
Although sprays may provide a quick, temporary knockdown of cockroaches, they do not give long-term control. They are likely just to disperse cockroaches to other areas of the building from which they may return later. 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.
Insecticide treatment of breeding sites for oriental and American cockroaches, including inside meter boxes, under uplifted concrete or on sewer lids, or around landscape plantings may be required when populations of these species are high and moving into adjacent buildings. However, an occasional cockroach observed in these sites does not indicate a need for treatment.