View report page

33
7. While the majority of tenants were helpful, re-visits were necessary several times
in some cases. It was found necessary to serve Sanitary Notices in some
instances.
General Observations.
Of the 494 houses inspected 147, or approximately 30 per cent., were found to
have evidence of vermin infestation. It is doubtful whether more than a very small
proportion of these would have come to the notice of the Department by complaint
in the absence of the scheme. Apart from this, disinfestation in adjoining houses is
much more useful than disinfestation in scattered lettings.
In addition certain other infestations were also brought to light, such as a very
heavy cockroach infestation which was dealt with separately. Within its limitations,
the scheme has proved useful and its continuance was approved.
Ashburton Grove Depot—Blowfly Infestation.
The infestation of Ashburton Grove Depot and the adjoining railway property
has been a serious and regularly recurring summer problem, and during the year
under review the Council carried out extensive measures in conjunction with
representatives of the Department of Scientific and Industrial Research with a view
to finding out the best method of combating this fly nuisance. The blowflies and
blowfly maggots are brought in with the refuse from four Boroughs, and the maggots
complete their life cycle at the Depot to the extent of millions or tens of millions
every season. It, therefore, became a major problem to break the cycle of reproduction
at some stage. Experience proved that it was difficult to kill maggots directly in
adequate numbers, the principal maggot infestations being in the soil between and
immediately adjacent to the railway tracks. Therefore no attempt was made to deal
directly with maggots.
The technique adopted, therefore, was aimed at covering the whole of the ground
with insecticide and keeping it covered by repeated treatments in such quantities
as would ensure that whenever the maggots emerged from the ground and hatched
into flies there would be sufficient insecticide to be picked up to ensure that the vast
majority of newly hatched flies would die from the effects.
Arrangements were made with the D.S.I.R. for representatives of that
Department to be allocated certain areas for experimental purposes, and it was
therefore necessary that these should be carefully avoided by the Council's operators.
The insecticide used by the latter consisted of 5 per cent. D.D.T. in powder
form, sprayed by powder-blowers which were hand operated. Areas only lightly
infested were treated less frequently than the heavily infested portions.
One of the Sanitary Inspectors was deputed to supervise this work, and was
assisted by two operators. With regard to the frequency of dusting, daily treatment
was carried out on one loading bay and the sites used for depositing fish and fruit
boxes and broken glass, twice-weekly treatments being carried out on the railway
tracks taking much-infested waggons based outside the D.S.I.R. special treatment
areas, treatments once-weekly on further tracks, and occasional treatment in certain
other areas.
During June, the infestation was relatively light, but at the beginning of July
the number of flies showed a marked increase, and heavy maggot infestation became