Cockroach Control, Cockroach Extermination, Cockroach Exterminator, Getting Rid of Cockroaches

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Cockroaches

Cockroaches are close relatives of termites. They represent a primitive and highly successful group of insects whose origins extend back at least 300 million years. Fossil evidence suggests that little change in their general body form has occurred since that time.

As a group, cockroaches can be found in a diverse range of ecologies, living in decaying leaf matter, under bark, in caves and burrows, on the foliage of shrubs and in the nests of social insects, boring into wood and even adopting a semi-aquatic habit. While there are about 3,500 species of cockroach worldwide, there are 428 species in Australia, but only about ten of those species have seriously exploited the dwellings of humans. Some species have become very successful scavengers that cohabit with people in many, indeed most, of the human communities around the world.

Most pest cockroaches that occur in Australia and many other countries probably originated in tropical or subtropical Africa, their worldwide distribution attributed to transport in ships, carriages, and later trains and aeroplanes, facilitated by a remarkable degree of adaptation to built environments. In dwellings and various utilities for waste disposal, people have created conditions that make food, shelter and often suitable temperatures available to these opportunistic insects.

Their wide distribution and close association with humans, coupled with the high frequency with which they carry human diseases, in and on their bodies, have given them a very high pest status in most parts of the world.

Species commonly found in Melbourne
The two main species of pest cockroaches commonly found in Melbourne, are the Australian Cockroach and the German Cockroach:

Australian Cockroach

This native cockroach is approximately 30-35mm in length, brown with a clearly defined yellow border around the pronotum (head section cover of outer shell) and yellow on the edge of forewings. Wings cover the abdomen. Mostly an ‘outdoors type’ cockroach that prefers plant materials, often found under bark of trees, among woodpiles, and in other locations that offer moist, decaying vegetable matter. Also found in subfloors, wall voids, garages and sheds. May fly in warm weather.

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German Cockroach

Considered a small species, the German Cockroach is approximately 12-15mm in length, light amber brown with two dark longitudinal stripes on pronotum. It commonly infests the interior of buildings, mostly in and around kitchens (domestic and commercial pantries, storerooms and other food handling areas). Also found in and behind stoves, sinks, refrigerators, water heaters and various other appliances. The German Cockroach prefers to be close to food, moisture and warmth. It does not fly.

Structure
Adult cockroaches are medium to large insects that, viewed from above, are mostly oval shaped, with the head hidden beneath the pronotum (head section cover of outer shell). They have long and slender thread like antennae, legs well suited to running, well developed compound eyes and chewing mouthparts. Wings may well be developed, reduced or absent. In fully winged species, the forewings are narrower and thicker, covering and protecting the more membranous hindwings. The abdomen is large and carries a pair of unusually large cerci at the rear.

Nymphs (young) are mostly similar to adults except in the development of wings, genitalia, and sometimes body colouring.

Life Cycle
Most cockroaches reproduce sexually and this often involves pheromones (usually secreted by the female and detected on the male’s antennae. Eggs developed in the female are encapsulated in a purse shaped egg case (ootheca) and may contain about 12-40 eggs, depending on the species and conditions of growth. The egg case may be dropped or glued to a surface just prior to, or months before, hatching. After hatching the nymphs tend to congregate with the adults, co-existing in a group. Development involves a number of moults and may take 2-4 months in some smaller species, or up to a year or more in others. Adult lifespan may be a few months to over a year, and in this time each female may produce about 5-30 egg cases, depending on the species and conditions of growth.

Habits
Typically, infestations of pest cockroaches develop in and around buildings and other structures that provide food, shelter and often the preferred conditions of temperature and humidity. A commercial kitchen may support hundreds or even thousands of cockroaches at varying stages of development. They may be carried from place to place as live individuals or as egg cases, in foods and their packaging, luggage, furniture, buses, trains, ships and aeroplanes.

SOME ASPECTS OF COCKROACH HABITS AND BEHAVIOUR WARRANT CONSIDERATION:

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Omnivorous feeding habit
Cockroaches will eat just about anything. Beside human foods and waste, this includes leather, cardboard, fabrics, hair, glue, wallpaper glue, starchy bindings in books, and even soap. They are most effective scavengers. Those bred in laboratories often subsist well on water and dog biscuits. In buildings, dried beer on carpets, spattered grease droplets and tiny crumbs can all supply nutriment. The importance of scrupulous housekeeping in any cockroach control program cannot be over-emphasised.

Nocturnal behaviour
Cockroaches are mostly nocturnal creatures which hide during the day and become active soon after the onset of darkness, seeking food. In some cases activity patterns are based on sunset, while in other cases the lighting regime within a particular building dictates activity patterns. Occupants of infested dwellings are often unaware of the extent of cockroach activity that commences after dark. Night inspections of cockroach infested premises can reveal much about the size of the infestation, feeding habits, hiding places, and so on. Active cockroaches observed during daylight hours often indicate overpopulation.

Grooming behaviour
Like many other animals, cockroaches frequently indulge in grooming themselves. This behaviour probably plays an important role in keeping sensory receptors clean and well functioning. Grooming often consists of running the antennae and legs through the mouthparts with a nibbling action. This behaviour may be used to advantage in their control. Dusts, and to some extent other types of formulation are picked up on the body and ingested during grooming.

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Cockroaches as pests

Cockroach species that have established some type of cohabitation with humans are widely regarded as pests. While their role in the transmission of diseases to humans is usually the main concern, there are various reasons for pest status:

Contamination
Cockroaches may contaminate food products, utensils and various areas with droppings, cast skins, empty egg cases, dead cockroaches and vomit marks on surfaces.
Annoyance or fear reaction
Many people are annoyed or scared by the sight of cockroaches. This may be related to their fast, unpredictable movements and perhaps very spiky legs. Many find their presence abhorrent.
Odour
Where a substantial cockroach infestation exists, an unpleasant odour may develop, owing to secretions from the mouth and cuticle.
Allergic reactions
Some people are allergic to cockroaches. Extracts of cockroaches can bring about positive skin reactions in sensitive people, and may cause asthma attacks in athsmatics. The allergen may be ingested where foods are contaminated with faeces, or inhaled when dried faeces become house dust.
Bites
Cockroaches have been known to bite people, although such incidences are rare.
Disease transmission
Cockroaches carry diseases of humans. Although cockroaches have never been irrefutably proved to have transmitted pathogenic diseases to humans, several factors point to the likelihood that they play an important role in such disease transmission. (eg. due to the nature of them dwelling in sewers, grease traps and other sources of polluted water).

Cockroach control

Effective control of pest cockroaches in and around buildings often relies on:

1) a comprehensive inspection/survey of the building(s);
2) a high standard of sanitation and hygiene, which will reduce the food, water and shelter that facilitate population growth;
3) the application of insecticides in a manner that makes likely their contact with the insects; and
4) follow up inspection and monitoring (that may involve the use of traps in some situations).

Such a combination of chemical and non-chemical methods of control usually relies heavily on the co-operation of those in charge of the building concerned.

The problem of reinfestation at some time after a treatment program, is a very real one. One source of reinfestation may be the subsequent hatching of egg cases that were present during the treatment but not directly affected by insecticidal action. Alternatively, reinfestation may arise from untreated adjoining areas. Where possible, treatments in larger buildings should deal with all sites of infestation during one ‘extended’ treatment. This makes necessary an initial extensive survey and thorough inspection of all the areas concerned.

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