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80
Disinfestation of Verminous Premises.—D.D.T. in kerosene
continues to give good results in dealing with verminous premises
when alternated with other vermicides such as Chlordane, Lindane
and Malathion, etc., to counteract the development of organismal
resistance.
During the year the department dealt with 42 cases of dirty
and verminous premises compared with 75 in 1961. The disinfestation
staff sprayed 123 rooms and contents as compared with 240
last year. In 2 cases the bedding and effects were removed to the
Council's disinfecting station for treatment by steam or formaldehyde.
Of other pests which necessitated the treatment of 1,313 rooms
and 241 external areas, the following initiated the greater number of
complaints.
Ants. Ants carry no disease but their presence in human foodstuffs
is objectionable.
Foods of a relatively high sugar content are particularly attractive
to ants and the insects are prepared to go to great lengths in
order to obtain a sufficiency for their community.
In the main, the 107 complaints received and the further
8 cases found on survey concerned either the black garden ant
(Lasius niger) or the yellow meadow ant (L. flavis), the workers
of which will gain access to houses through cracks in the walls or
floors, over sills or through window frames in search of food and
152 treatments involving 223 rooms and 90 external areas were
carried out to combat the reported nuisances.
One of the commonest of ants, the very small red House or
Pharoah's ant (Monomorium pharaonis) was also the cause of a
number of complaints.
This species, being of tropical origin, is incapable of breeding
in England without artificial heat. A temperature of approximately
80°F is considered to be ideal for its propagation and ipso facto il
is found infesting bakehouses, restaurants, hospitals and houses
especially in larders and kitchens and nests may be found behind
wall plasters, behind pipes or ovens, in heating ducts and under
floor coverings and foundations.
As in previous years this pest was encountered at two of the
large hospitals in the Borough where, despite intensive investigation
the sources of infestation were not located.
The total number of treatments carried out in respect of this
ant was 38, a decrease of 19 from the previous year.