Cockroaches
Cockroaches are
one of the most common household pests. Although most cockroach species are
tropical in origin the main pest species have adapted their habits so that they
are now found living alongside humans in temperate, sub-tropical and tropical
climates. They are active mainly at night and hide in cracks and crevices during
the day preferring dark moist sites often in basements or sewers. Cockroaches
will eat most things including meats and grease, starchy foods, sweets, baked
goods, leather, wallpaper paste etc. All cockroaches have dorso-ventrally
flattened bodies and in several species the adults are capable of gliding
flights.
There is no clear evidence to link cockroaches to disease outbreaks but they are
well known to be incidental carriers of micro-organisms because of the habitats
in which they live including sewers, heating ducts, waste disposal areas. This
incidental transfer of micro-organisms is likely to contaminate foods and
produce spoilage and cause gastro-intestinal illness in people. Cockroaches are
therefore considered passive disease vectors.
Disease organisms found on cockroaches include:
Salmonella (food poisoning)
Mycobacterium tuberculosis (tuberculosis)
Entamoeba histolytica (Ameobic dysentary)
Escherichia coli (Gastro enteritis)
Ancylostoma spp. (Hookworms)
Taenia spp. (Tapeworm).
Cockroaches also produce antigens from their bodies and excretions and these can
be important triggers for asthma and other allergies in humans. Up to 60% of
asthmatics have an allergic reaction to cockroaches which is only second to the
house dust mite in its ability to trigger allergies.
There are four species of cockroaches that are commonly considered pests:
American Cockroach German
Cockroach Oriental
Cockroach Brown Banded Cockroach
Cockroach Facts
Cockroaches are amongst the most ancient insects. Fossil records indicate that
cockroaches were around some 350 million years ago
Cockroaches are a major cause of asthma and allergies
Doctors in some inner city areas report that 50% of the foreign objects they
remove from children's ears are cockroaches
Cockroaches will feed on people! They feed at night when people are sleeping and
consume protein materials including eyebrows and fingernails
Cockroaches are amongst the fastest land-moving insects. They are capable of
moving 50 body lengths per second that is equivalent to a human running 100
yards in one-second (200 miles per hour)
American Cockroach
The American cockroach, Peripatetic americana, is the largest of the common
cockroach species measuring 28-44mm in length. It is dark brown to dark red in
colour with light markings on the thorax. Both sexes are fully winged with the
male wings extending to just beyond the end of the abdomen while the wings of
the female is the same length as the abdomen. Egg cases or oothecae are simply
dropped in a suitable location or glued to a surface with oral secretions. Once
mated a female will produce oothecae at a rate of one per week with a total of
15-90 capsules being produced in her lifetime.
Each ootheca contains 14-16 eggs. At 21C the nymphs hatch in 45 to 55 days. At
the time of hatching the nymphs moult and leave a thin cast skin in the egg
case. Under ideal conditions nymphs pass through 7 - 15 moults in approximately
5 months before they become adults. If conditions are unfavourable this can take
up to 24 months.
American cockroaches prefer a warm, moist habitat and are common in food
handling establishments and industrial plants. In tropical or sub-tropical
climates this species will live outdoors. The American cockroach may travel
directly from the sewer to houses and in doing may carry microbes on its body
that can contaminate food and food preparation areas.
German Cockroach
Blattella germanica is perhaps the most common cockroach in the UK. This species
is light brown in colour with two dark stripes on the thorax. It is small in
size measuring approximately 12-15mm in length. Both sexes have well-developed
wings which over-lap the end of the abdomen but generally this species is
reluctant to fly. Unusually the female carries the egg case until hatching is
imminent. Each ootheca may contain from 18-50 eggs and a female will produce
from 4-8 egg cases in her life time. Eggs hatch in about 30 days and over a
6-week period nymphs will moult 5-7 times before becoming mature. In less
favourable conditions nymphal development can take up to 6 months but typically,
at room temperature, the average life cycle takes 60 days. The German cockroach
is typically found in warm dark places where there are a lot of small cracks and
crevices. The location will usually be moist or located near water sources and
food supplies.
German cockroaches usually cluster together and adult females with ootheca are
usually found deeper within the harbourage than other life stages. The German
cockroach is most active at night in dark areas but it is not unusual to see
them during the daytime if the area is relatively undisturbed.
This species prefers high relative humidity and warmth and is a significant pest
problem in homes, restaurants, hotels, food plants, office buildings, hospitals,
ships and retail outlets. It is quite active and can readily migrate through out
a building. This species prefers a kitchen or bathroom with plenty of food,
moisture and hiding places exist.
The Oriental Cockroach
Blatta orientalis is one of the commonest species of cockroach in the UK. This
species is usually found in areas of high temperature and high moisture levels
such as kitchens, laundry's and hospitals. The male has small wings, but is
unable to fly and the female has only vestigial wing stubs.
This species is dark brown to black in colour and approximately 25-30mm in
length. The female only carries the ootheca for about 30 hours before dropping
it or attaching it to a surface near to a food supply. The average female will
produce 6 capsule in her lifetime each with 16 eggs that hatch in about 44 days.
The nymphal stage lasts from 5-9 months during which the nymphs moult up to 10
times.
This species is more cautious and less active than other common cockroach
species. It may enter the home in food packaging or laundry or find its way in
from the outside. It is common in sewers, utility ducts, in dark, damp basements
and is know to enter the upper floors in blocks of apartments via the water pipe
system. It is most commonly found at or below ground level. This species is very
gregarious and commonly found in large colonies.
This is a relatively sluggish insect. It lives on filth and travels along sewage
systems into homes. It prefers damp cool areas, especially basements and near
drains and leaky water pipes. They can be found under sinks, refrigerators and
washing machines if these areas are damp.
Brown-Banded Cockroach
Supella
longipalpa is an African species but has recently become established in houses
in Europe. This is a gregarious species and often found in homes, hotels and
apartments rather than commercial properties and restaurants. This species
prefers to hide in warm elevated areas and is usually found near the ceiling,
behind wall decorations, pictures, loose wallpaper, underneath chairs and tables
and in electrical appliances such as televisions, stereos, radios and toasters.
They develop and live throughout a building that makes control more difficult.
An adult brown-banded cockroach is light brown to dark glossy brown in colour
and 12-14 mm in length and with fully developed wings. Males are capable of
flight. Nymphs and adult females are broad when viewed from above while males
tend to be slender. The males' wings cover the abdomen while those of the female
are short and expose the abdomen. This species has two light yellow or cream
transverse bands across the base of the wings and abdomen. These bands may
appear irregular or broken but are usually more apparent in the nymphs and
females. Egg capsules are about 5-6mm in length, crescent or purse shaped and
yellowish or reddish brown in colour.
This species deposits egg cases in clusters inside furniture, underneath tables
or chairs, on curtains, behind wall decorations and shelving. Each capsule
contains 14-18 eggs and a female will produce from 10-20 egg cases in her
lifetime. Eggs hatch in approximately 50-75 days and nymphs develop in 3-9
months. Adults live for approximately 6 months.
This species is most active at night and both nymphs and adults will jump
rapidly when disturbed. This species does not require as much moisture as the
German cockroach.
Advanced Rodent Control.