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Expert Opinion

Cockroaches: Common or Controversial?

By Dr. Stuart Mitchell

Traced back over 200 million years through the fossil record, cockroaches are primitive, but their diversity is almost unrivaled. Globally, over 4,000 species of cockroaches exist. Pest pressures are represented by about 50 species.

Pestiferous species originate from tropical countries. Resulting from international travel and trade importation, cockroaches can reside robustly within architecturally stable climates. With indiscriminate and omnivorous feeding behavior, cockroaches come into contact with numerous pathogens (such as those causing food poisoning and wound infections).

Common in private structures, commercial buildings, and food processing and handling facilities, cockroaches are gregarious and nocturnal. Cryptically in cracks and crevices, cockroaches pass diurnal hours in adjacency to sources of food and water (sinks, drains, cookers, backs of cupboards, in refrigerator motor compartments, etc.). Causing elimination challenges, some cockroach species prefer complex plumbing systems and service ducts within larger structures.

Poor sanitation and hygiene coupled with delayed maintenance issues supplies cockroaches with explosive population potentials. The species, source, and extent of infestation are discovered through inspection and investigation of the entire structure. The nature and extent of treatment (insecticides, proofing, and trapping) as well as resultant success or failure are dependent upon competent structural assessment.

The number of cockroaches observed is usually a small percentage of a much larger population. Infestation can occur when cockroaches are imported into premises on raw materials or packaging and enter through structural defects (damaged drains and drain covers, ventilation openings, under doors, etc.).

Evidence is a sign or proof of existence. Therefore intuitive inspection and investigation rely upon recognition of physical evidences.

Odor Evidence

Established cockroach populations exhibit a characteristic foul odor (produced by feces, salivary/abdominal gland secretions, and dead insects).

Marks Evidence

Established cockroach populations may be completely cryptic during daytime hours, but the marks left behind by cockroaches are evident on numerous surfaces. Most perceptible near cockroach harborages, brown, irregular streaks of liquid excreta are produced when water is readily available.

Harborage Evidence

  • In kitchens, behind and under sinks and appliances.
  • Around plumbing and radiators (especially where pipes pass through walls).
  • Inside cupboards, under tables, and behind wall tiles.
  • Inside plugs and wall switches.
  • Ventilation and service ducts.
  • Basements and crawlspaces, store rooms, utility areas, and floor cavities.
  • Brickwork and cracks in concrete.
  • Outbuildings, rough-ground, landscaping drains, tree holes, compost areas, and trash areas.

Live Cockroaches Evidence

  • Live cockroaches can be detected via a photometric inspection using a bright flashlight directed into harborages.
  • A night inspection will identify areas where cockroaches are foraging (graph areas during inspection).
  • Effective flushing can be accomplishing using compressed air.
  • Care must be taken to avoid contact of certain propellants near combustion appliances.
  • Crawling insect traps placed for one photoperiod will produce conformational evidence.

Its possible common cockroaches may no longer be the structural pests they once were, but they are very controversial as a public health challenge as well as capable of a strong resurgence.

From the PMP archive

Tips & Tricks: Keep cockroaches out
Cockroaches are one of the most common insect pests, in both residential and commercial accounts. In addition to transmitting bacteria through the building and triggering allergies in humans, recent reports have linked cockroaches to the development of asthma in children.

Cockroaches in the restaurant industry
For Patrick Hickman, service manager at OPC Pest Control in Louisville, Ky., it's not just any bed bug-infested apartment or lawn covered in fire ants that gets his blood pumping. His greatest satisfaction comes from facing his ultimate adversary: cockroaches in food-processing plants.

On the wire

Researchers use video game technology to control roaches
From Houston Chronicle (Houston, Texas)

Meet the man with 200,000 cockroaches for roommates
From Daily Mail Online (London, U.K.)

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