SEMI-FIELD TRIALS WITH SOME NEW ORGANIC INSECTICIDES
FOR THE CONTROL OF LICE ON LIVESTOCK
R. P. CHAUDHARI and PAVAN KUMAR, Indian Veterinary Research Institute, Izatnagar
Received on September 9, 1958 and accepted for publication on September 17, 1958
Lice are important ectoparasites of man as well as of animals. The human lice, apart
from their blood-sucking habit disseminate certain important diseases, such as relapsing fever
and epidemic typhus fever. Although so far no livestock disease is known to be disseminated
by lice in nature, lousiness is a rather important ectoparasitic ailment of livestock all over the
world and the monetary loss due to it is quite considerable. The annual loss to the U.S.A. due to
lice infestation on all classes of livestock and poultry has been estimated to be approximately 52
million dollars [U. S.D.A. Res. Service, 1954, quoted by Smith and Richards, 1955]. According
to Snipes [1948] lice-free cattle gained an average of 73 pounds more per head than the untreated
cattle under identical conditions over a period of 51 days. In other countries like Great Britain
[Craufurd-Benson, 1941] and Australia [Roberts, 1938] also, lice are considered as important
pests of livestock. Buffaloes, cow calves, goats and sheeps are very often found to be infested
with lice in this country. Different species of animals are infested with different species of lice.
Young buffalo calves, cow calves, kids, and sometimes even adult goats, die as a result of
heavy infestation with lice in this country.
Simmols [1946] reported that 0.3 per cent DDT dips served to eradicate cattle lice Haema-
topinus eurysternus and Damalinia bovis, but allowed light infestation of Linognathus vituli to persist;
0.28 per cent BHC (0.075 per cent gamma BHC) sprays freed the cattle of the above two
species of sucking lice immediately after spraying and the treated animals remained louse-free for
eight weeks. Similarly, Annand [1947] reported that 0.08 per cent was found to be the minimum
concentration of DDT required in dips to kill all the motile forms of the cattle lice, H. eurysternus
and D. bovis but 0.15 per cent was required to control all the motile forms of L. vituli and Soleno-
potes capellatus. There was no evidence of eggs of these lice being killed by the treatment. The
residual effect of the treatment remained for four or five days. A second treatment sixteen
days after the first eliminated the infestation. Creighton and Dennis [1947] found that a thorough
application of 2 per cent DDT (emulsion) spray applied to all animals in the herd would result
in complete elimination of the cattle-tail louse, H. quadripertusus. However, the authors suggested
that a follow-up application within 21 to 28 days would be economical. Sweetman [1947]
found that sprays containing 0.2 per cent DDT and chlordane freed hogs of the louse H. suis in
about 2 hours and the treated animals remained free for three weeks. When the hogs were
sprayed in November no louse was seen on them during the following three months. How-
ever, newly hatched larvae were observed about two weeks after a herd was sprayed with 0.2
per cent DDT in late October. Brown [1949], while testing the effect of a specially prepared
DDT emulsion containing 0.25 per cent DDT, 2.5 per cent xylene and 0.6 per cent laundry
soap against the goat louse D. limbatus found that when examined 24 hours after dips 32 per
cent of the goats showed light surviving infestation, but after 48 hours of dips no louse was seen
on any of the treated goats. When the treated goats were examined two weeks after the treat-
ment all were free of lice but 15 weeks after the dips 7 per cent of the goats showed very light
infestation.
Wells and Barrett [1946] reported that the eggs of H. eurysternus were completely killed
by treatments with even 0.1 per cent gamma BHC. Furman [1947] stated that eggs of this
species of cattle lice thoroughly drenched with 0.06, 0.125, 0.25 and 0.5 per cent BHC failed
to hatch but following a light spray of BHC at 0.1 and 0.125 per cent many eggs hatched.
On the other hand, even thorough drenching with aqueous suspension of 0.125 and 0.5 per
cent DDT failed to prevent hatching of many eggs. The same worker found that infestation of
H. eurysternus and L. vituli was eradicated by a single dip in a 0.3 per cent suspension of BHC
(equivalent to 0.036 per cent gamma isomer) and D. bovis was eradicated by a single dip in