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221
Four treatments involving 9 rooms and one external area were
carried out in respect of this ant.
Cockroaches. The cockroach (Blatta orientalis) and its smaller
relative (Blattella germanica) are well known for their destructiveness,
especially in relation to stored organic matter, ranging from foodstuffs
to book bindings. Food is rendered repulsive from contamination
not only with their faeces but also with the secretion from their
scent glands, and the cockroach is strongly suspected of transmitting
to man a number of pathogenic organisms especially those of an
enteric nature.
Cockroaches shun the light and are most active during the night.
Warmth, moisture, darkness and close proximity to food supplies
constitute favourable conditions for breeding.
Forty-five complaints were received concerning this pest and
thorough investigation and treatment with Dieldrin Concentrate
resulted in the infestations being considerably reduced. In all, 45
treatments were effected involving 179 rooms.
Clover Mite. Six complaints were received, mainly from tenants
in blocks of flats in various parts of the Borough, concerning small
red or dark brown insects (Bryobia praetiosa) found moving over
walls and windows. On each occasion spraying of exterior surfaces
with Dieldrin Concentrate produced satisfactory results.
Wasps. Complaints received implicated three types, the Common,
the German and the Tree wasp. (Vespula vulgaris, V. germanica and
V. sylvestris).
Fear of the wasp is often misplaced for they rarely sting unless
they are roused or frightened and, contrary to popular belief, wasps
are not entirely harmful for in Spring and early Summer they feed
mainly on insects, many of which are themselves injurious. However,
after mid-summer their diet becomes more vegetarian and the
workers feed on ripening fruit and other sweet substances, thus
effecting serious damage in orchards, sugar warehouses, grain
factories, etc., where they cause considerable wastage of goods. In
houses they become a nuisance during cooking and at meal times
and it is conceivable that they are instrumental in the spread of food
poisoning.
The queen wasp, the only survivor from the previous year's
colony, emerges from hibernation in the Spring to choose a site for
nesting, usually in cavity walls, lofts, under roof tiles and other sites
which evoke a certain ingenuity on the part of the disinfestors in
order satisfactorily to deal with the nuisance.
One hundred and sixty-one complaints regarding this pest were
received and during the year some 123 nests were destroyed, mainly
by means of Gammexane powder or Dieldrin Concentrate.