|
The Oriental cockroach, Black beetle,
Black lock or Shad roach, to give it just a few of its
common names, is thought to have originated from North
Africa. It is now widely distributed in almost all temperate
regions of the world, preferring less humid and cooler
conditions (22-27°C) than other cockroach species such as
the German, Blattella germanica,
and American / Australian, Periplaneta spp. It has been
shown to be able to survive the winter outdoors, notably in
refuse heaps.
The adult Oriental or Common cockroach is
large (20-24 mm long) dark redbrown to black. Most people
would be able to recognise this species as a cockroach,
unlike some of its smaller cousins. The male is winged, but
the female has much reduced, vestigial wings and tegmina.
However, neither sex is able to fly.
The species is principally nocturnal and
so not often seen during the day -any daylight sightings
suggests a heavy infestation or a newly introduced specimen
searching for a harbourage. The egg case (ootheca) is about
10-11 mm long, is brown-black and deposited by the female
soon after formation. Oothecae are produced at about 10-day
intervals and contain about 16 eggs. Cockroaches have an
incomplete metamorphosis (egg, nymph, adult). There are 7-10
nymphal stages, development to adult taking 6-12 months in
heated buildings.
The adult life span varies from 2 months
under warm conditions to 9 months in cool conditions.
Reasons for control
B. orientalis is
now known as a major pest of buildings, notably in cellars,
basements, ducts, boiler rooms, kitchens, bakeries, toilets
and bars. It is the major cockroach pest in Britain.
Because of its habits and feeding sites,
it is a potential carrier of pathogenic bacteria when
associated with food. People also find their presence and
odour repulsive. A recent study in the USA suggests that
nearly one fifth of the population is allergic to
cockroaches, their droppings, odour and breakdown products.
|
