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Rodent Control.
Rat destruction is carried out both by trapping and
poisoning. In the Stepney scheme poisoning is the method
mainly used. The usual poisons are zinc phosphide and
arsenous oxide, A new poison, Warfarin, has come into use
since 1951, and during 1953 we made greater use of it in
Stepney, and are finding it very effective.. Warfarin is a
powder which acts by preventing normal blood clotting.
After absorption over a period the rat dies from internal
haemorrhages.
One of the problems associated with the use of Warfarin
has been to find a suitable base with which to mix it.
We have found medium grade oatmeal a satisfactory base in
most cases, A new base more attractive to the rats is now
recommended by the Ministry of Agriculture and Fisheries,
and consists of pihhead oatmeal, castor sugar and technical
white oil or light liquid paraffin B.P, This may help to
overcome the difficulty of dealing with rats in infested
premises where rat-attractive foods are normally, stored.
Warfarin can also be used as a rodenticidal dust, i.e.
mixed with an inert powder spread fairly thickly on the rat
runways. The powder thus adheres to the feet and bodies .of
the rats and mice, and is absorbed by them in the normal^
process of cleaning themselves by licking.
This method cannot safely be used with poisons other
than anticoagulants of the Warfarin type, because the concentration
required would involve risks to humans and domestic
animals. In the strength used, the anticoagulant dusts are
only lethal after repeated contamination spreading over
several days.
In accordance with a request of the Ministry of
Agriculture and Fisheries, statistics on rodent control work
carried out by the department which were submitted to the
Ministry covered the period 1st January, 1953, to 31st March,
1954, Future annual reports will cover the period 1st April
to 31st March. During the 15 months under review, 13*613
dwellings and business premises were inspected. Charges for
servicing made to occupiers of business premises amounted to
£1,189.
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