Bayer Environmental Science :: Cockroach Biology

Cockroach Biology

Believe it or Not	Valuables
Introduction Cockroaches have existed on earth for at least 250 million years, having changed very little since the Carboniferous period. There are about 3,500 species of cockroaches, some of which concern man by assuming the role of a loathsome pest. Medical Importance Cockroaches carry many pathogens by their habit of regurgitating food and defecating while feeding. Movement from unhygienic areas into houses can cause mechanical contamination of food with viruses, bacteria, protozoa, helminthes and fungi, causing enteric fever, gastro- enteritis, intestinal infections, food poisoning, dysentery, diarrhoea and other disease conditions Habitat and behaviour The domiciliary species prefer an urban and moist environment. They are mainly found in kitchens, larders, restaurants, door frames, cupboards, electrical boxes, drains and sewers, cracks & crevices. Domiciliary cockroaches are nocturnal. They forage for food at night and hide during the day. They can migrate from house to house through sewers. They are very sensitive to vibrations and disturbances, quickly scurrying for cover.	Cockroach control will only be successful if we know: Which species is it? Where do the adults and the juveniles hide, and where do they move around? What is the source of the infestation, and how are the insects getting into premises? These questions must be answered by means of an assessment, such as using sticky traps, before a campaign begins. Integrated pest management is particularly important when it comes to cockroaches. Control and cleaning of an infested area should always be done from the outside in to prevent the insects from fleeing. First, rooms should be cleaned and food removed. Cracks and hollow areas resulting from poor construction should be sealed off. Contact insecticides (powders, sprays, fogging agents) and baits are available for chemical-based control. The egg capsules are usually insensitive to insecticides. It is thus not unusual to see the reappearance of insects a few weeks after initial control; a number of time-delayed campaigns are necessary. If care is not taken, they can quickly re-enter sensitive areas. Modern bait formulations to control cockroach infestations allow highly targeted application close to the cockroach population. Cockroach gels are ideally suited to food handling areas, restaurants, supermarkets, hospitals, nursing homes, schools, hotels and other sensitive areas. In contrast to the application of conventional fogs or liquid sprays, cockroach gel application does not require extensive preliminary preparations. Special protective clothing as prescribed for application of sprays is not necessary. Cupboards do not have to be emptied, occupants do not have to leave during treatment and there is no smell. The normal operation of kitchens, restaurants, offices etc. can continue and people do not need to leave the area. Very little active ingredient needs to be applied to achieve extraordinary results. Cockroach gels should be applied by placing the applicator tip into cracks, crevices, holes, voids, hollow spaces in floors, walls, ceilings, equipment legs, utility entrances, around drain pipes, behind or under cabinets, refrigerators, sinks, stoves, dishwashers and other equipment where cockroaches may hide or have their nests. Gaps through which they may enter the building also need to be treated. Of course, cockroach gels are also intended for use in non-food/feed areas such as garbage rooms, lavatories, floor drains to sewers entries and vestibules, offices, locker rooms, machine rooms, storage rooms, aircraft and so on.
	Facing Facts
	There are three main cockroach pest species in South Africa: German cockroach (Blattella germanica) American cockroach (Periplaneta americana) Oriental cockroach (Blatta orientalis) German cockroach (Blattella germanica) Size: Up to 16 mm Appearance: Light brown appearance with characteristic dark stripes on thorax Where found: Worldwide, resides in nearly every part of human habitats Agility: Good climber, even on very slippery surfaces, cannot fly Food: Omnivore Reproduction: Females carry egg capsules until shortly before they hatch, depositing them near moisture sources, 2-3 month development time from egg to adult, 36-egg average, 100-200 day life expectancy, population multiplies very quickly American cockroach (Periplaneta americana) Size: Up to 53 mm Appearance: Medium brown Where found: Tropics and sub-tropics, prefers warm site in temperate climates, sewers, warehouses Agility: Poor climber, both sexes fly well and far Food: Omnivore Reproduction: Females deposit egg capsules anywhere, 600 day development time, 15-20 egg, up to 400 day life expectancy Oriental cockroach (Blatta orientalis) Size: Up to 32 mm Appearance: Dark brown Where found: Worldwide, prefers warm areas such as bakeries, breweries, dairies, sewers Agility: Not a good climber, cannot fly Food: Omnivore Reproduction: Females deposit egg capsules in warm and moist sites, 2-6 month development time, 15-egg average, 150 day life expectancy All three species almost never fly and Oriental roaches cannot fly. They may glide for short distances.