Cockroaches
Key
Features of Cockroaches
Sometimes confused with black beetles from
the garden, cockroaches are distinguished by their very
long whip-like antennae, flat oval bodies and rapid,
jerky gait. The adult German cockroach is 10 to 15mm
long. The Common or Oriental cockroach is 20 to 24mm
long. They are rarely able to survive out of doors in
the British climate, but thrive around the heating ducts
and boiler rooms of large centrally heated buildings
e.g. hospital, bakeries, hotel and restaurant kitchens,
laundries and blocks of flats. They cluster around pipes,
stoves, sinks, especially in humid areas.
Biology
The German cockroach carries its egg case, a small brown
purse-like capsule, until the 30 or more nymphs hatch
from it. The Oriental cockroach deposits its 13mm long
egg capsule on packaging, sacking or in suitable dark
crevices before the 16 or 18 nymphs hatch out. Cockroaches
grow by stages - from "mini-cockroach" nymphs
to maturity in six to 12 months for the Oriental cockroach,
but only in as many weeks in the case of the German
cockroach.
Distribution
Cockroaches are found throughout Europe and the Americas,
particularly in warm, humid climates.
Significance
Both German and Oriental cockroaches eat any sort of
food and emerging after dark, from their inaccessible
harbourages to forage, contaminating food and food utensils,
or food preparation surfaces as they go. They taint
food with an obnoxious smell and may be carriers of
various diseases, including serious food poisoning.
All the nymphal stages and the adults feed on the same
type of food, making the establishment of an infestation
extremely easy.
Control
Infestations can become very quickly established and
can be very difficult to control, because the populations
increase rapidly and cockroaches are incredibly hardy
– they can survive long periods without food or
water.
However, once the source of infestation, the species
of roach and their harbourages have been identified,
cockroaches can be effectively controlled using an integrated
approach, incorporating baits, sticky traps, insecticidal
dusts, growth regulators and proofing against further
infestations.
Post-treatment monitoring is essential and re-treatment
will almost certainly be needed.
