It may be concluded from the experiments conducted which, though on a
small scale, nevertheless represent a severe test of the insecticides used, that
Dieldrin is an extremely potent and quick-acting acaricide. Against Psoroptes
communis avis it is able to control sheep scab with a single dipping at a concentration
of 0•03 per cent of the active ingredient. Its acaricidal action at this
strength is comparable to that of gamma B.H.C. at 0•02 per cent. Aldrin in
wettable powder or emulsion form, at a concentration of 0•05 per cent of the
active ingredient must be regarded as not being sufficiently effective to eradicate
scab with a single treatment.
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