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killed most of the grubs. From two to four treatments "'ere reauired. 
An anonymous (l_) writer in 1931 reviewed s report in the York- 
shire Post by R. C. Geut, Agricultural Organizer for Worcestershire, 
Englend, on the value of derris in combating ox ^rbles. About 10,0^0 
head of c?ttle "^ere dressed 4 times ^ith a preparation made according 
to the Bishoup et al. (29) formula. The fine particles carried in the 
soapy "ash during dressing effectively plug the breathing holes of the 
grubs, causing death by suffocation. There is thus a dual action, 
"hich makes a 100-percent kill possible. The -rash should therefore be 
kept 'Tell agitated bv means of the cloth and hand so that little or no 
"mud" remains at the bottom of the vessel when the liquid has been used 
up. 
An anonymous (2) writer reported in 1931 that tests made on one 
animal with the "Derrifluid" of Tropper showed good effect on Hyooderma 
larvae "hen the material was injected, but poor results from external 
application. The injection was easy and without harmful after effects. 
Compton ( 60 ) in 1931 gave an account of an eradicatinn campaign 
carried on in Illinois, with Gusanol, a proprietary derris extract 
ointment. The treatment v?r-g started about February 20 and was given 
at 30-day intervals until about the first of July. It is estimated 
that f,his treatment reduced the ox varble "copulation 65 percent. 
The Ministrv of Agriculture and Fisheries of Great Britain ( 124 ) 
in 1931 estimated the annual loss in Great Britain from hides damaged 
by garbles at more than 500,000 pounds sterling. Preparations of derris 
root "ere very effective in destroying "arble larvae. T ,j '0 proprietary 
derris preparation «ere used — (l) an ointment, and (2) a "ash prepared 
from a ponder sold as an insecticide. It ^as claimed that both the 
ointment and the "ash, "hen carefully ap-plied, would kill' practically 
all the mature or maturing warbles at a cost in materials of about 1 
pennv per head, for the four applications. No harmful effects to the 
cattle were recorded. When the ointment is used each "arble hole must 
be located and treated after being freed from hair. The wash is more 
convenient to apply, a? it is only necessarv to locate the spellings 
and then liberally "et each one "ith a soft cloth steeped in the 
-preparation. 
Zaubzer (330) in 3931 reported on warble fly control in Bavaria. 
Mechanical removal has given better results than any other method, 
including Hypodermol, a largely used salve containing paradichloro- 
benzene, derris, and laurel oil. 
The University College of North Wales, Department of Agriculture 
( 220 ) in 1931 repeated its recommendations of 1930 for warble fly 
control by means of derris. 
Reisinger ( 236 ) in 1931 recommended the follo'-i.ng proprietary 
derris products for "arble control: Cooper's Salve, Derrifluid, 
