by Nick Gromicko
Cockroaches are one of the most commonly encountered household pests. Homeowners and inspectors can learn about ways to eliminate these insects and the conditions that encourage their infestation.
Cockroaches have a broad, flattened body and a relatively small head that covers their mandibles and other mouthparts. They have six legs, large ocelli (simple eyes), and a pair of long, flexible antennae. Although winged, they are not adept fliers. The best-known varieties are the American cockroach (1.2 inches long), the German and Asian cockroaches (0.59 inches long), the Oriental cockroach (0.98 inches long), and the brown-banded cockroach (0.55 inches long).
Facts and Figures
- The world's heaviest cockroach is the Australian giant burrowing cockroach, which can weigh more than 30 grams and reach 3½ inches in length.
- While cockroaches could withstand six to 15 times as much radiation exposure as humans, the popular belief that they will “inherit the Earth” in the wake of nuclear war is largely undeserved; other insects, such as fruit flies, have even better resistance against radiation than cockroaches.
- While it has been known for some time that cockroaches and termites are related, it wasn't until 2007 that it was proven that termites are a kind of "social cockroach," having actually evolved from cockroaches. Similarities include specialized casings that enclose their eggs, perforations in the internal parts of their heads, and similarities among their young. There are significant differences between these pests, however; termites pose a greater danger to wood, and they form huge, complex societies, while cockroaches are solitary, generalized insects with few special adaptations.
- Some species of cockroaches can survive for months without food and subsist on nothing but the glue on the back of a postage stamp, and even their own feces. Experiments have revealed that they can go without air for 45 minutes and recover after being submerged under water for half an hour.
- Cockroaches are prolific breeders and can produce several thousand offspring in a year, once they become established in a home. They are normally introduced on clothing, shopping bags and furniture, and they can also simply wander in from the outdoors.
Cockroaches are known to spread diseases such as salmonella, food poisoning and dysentery, primarily through contact with their feces and defensive secretions. They also transport dangerous microbes, a particular problem in hospitals. Their skin, which is discarded through periodic molting, can become airborne and trigger severe asthmatic reactions in prone individuals. Incredibly, cockroaches have even been found to be second only to house dust as the worst allergen affecting people, according to the University of Kentucky’s College of Agriculture. Besides these physical ailments, cockroaches emit an unpleasant odor during swarming and mating, and they can keep a building's occupants awake at night with their incessant hissing and, in the case of some cockroach species, chirping.
InterNACHI inspectors should not be surprised to find evidence of cockroaches in messy buildings, as the insects thrive in dirty environments. No buildings are completely immune to cockroach infestation, however, as they will be attracted to even the smallest amounts of food deposits. They prefer to feed on decaying grease, sugar and other organic matter, as well as inanimate, starchy food sources such as glue, wallpaper and even book bindings. Pepper-like specs in kitchen cupboards are an indication of cockroach infestation, as is the observation of adult cockroaches or their egg sacs in hard-to-reach locations, such as cracks and crevices in kitchen cabinets, drains, and behind dishwashers and refrigerators. The entire kitchen area should be inspected, especially under sinks, in cabinet hinge areas, drawers, refrigeration gaskets, dishwashers, stoves and other cooking appliances. Also check crawlspaces, bathrooms and other dark, moist areas where food sources may be present.
Tips that inspectors can pass on to homeowners:
- Place boric acid in areas of cockroach activity. Boric acid can maintain an infestation once under control, but pyrethrin should be used first and the whole structure bug-bombed.
- Pyrethrin should be used first, and after the population is under control place boric acid wherever needed.
- Place bait stations containing hydramethylnon or fipronil in areas of termite activity. At night, homeowners can sneak into the kitchen and turn on the lights. If cockroaches scurry for cover, observe where they run and position traps accordingly.
- Keep all food in sealed containers, use trash cans that have tight-fitting lids, and do not leave pet food out overnight.
- Clean the kitchen regularly, and wipe moisture from the kitchen sink before going to bed at night.
- Vacuum frequently.
- Repair dripping taps and leaky pipes, broken roof tiles, and any other condition that might allow moisture to enter areas where cockroaches can establish harborage.
- Seal off all entry points into the house, such as cracks around baseboards, pipes, windows, cabinets, doors and crevices in bathrooms with copper mesh or steel wool and caulk or putty.
- Keep lights on at night. Although it will consume additional electricity, cockroaches will avoid lit areas. For the same reason, restaurant owners sometimes leave lights on around dumpsters.
- If cockroach infestation persists, contact a qualified exterminator.
In summary, cockroaches are hardy, disease-carrying household pests that can be controlled by maintaining a clean home and eliminating sources of moisture intrusion.