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Hearle (138) .in 1938 -published directions for preparing derris 
^a sh (derris powder 1 It,, soft soap 1/4 lb, water 1 imp, gal.) for 
use against cattle grubs. 
Thorns sen and Doner ( 274 ) in 1938 revie-'ed published information 
on fly control for livestock end mentioned rotenone for killing 
Hyp Oder .-ne larvae. 
Dinulesco andFoisoreano (75) in 1939 reported that in the labora- 
tory extracted grubs placed in contact with derris extract at the 
tempera.to.re of the host were killed after 5-1/2 hours, 
i/i. P. Jones ( 158 ) in 1939 recommended derris or cube for the 
control of cattle grubs, 
L. G. Snith ^ 256 ) in 1939 called attention to the control 
demonstration of cattle grubs carried out on a herd of 150 head of 
beef cattle in G-erfield County, Wash, Excellent results were obtained 
from 4 treatments beginning in December 1938 and applied every 20 
days. The ,T, ash consisted of 1 round of 5 percent cube root and 2 
ounces of soap in 1 gallon of water, applied to the backs of the 
animals at the rate of 8 ounces per animal, and thoroughly scrubbed 
in with a brush. 
Wells ( 310 ) in 1939 reported the results of a series of tests 
on the use of derris and cube raphes on the backs of cattle for con- 
trol of cattle grubp in Colorado and Iowa. Bv using derris and cube 
cashes (1^42, 6, and 4 oz. plus 4. oz, soap per gallon of ^arm 
water) 011 the backs of cattle, it was found, that 1 quart of the 
solution ^es sufficient to treat only 3 animals with such winter coats 
as are found in Colorado and Iowa. After distributing the powdery 
•^ash over tho lock it was necessary to devote 2 man-minutes of rub- 
bing the wash into- the hair with the hands. Rubbing ^i th a brush 
was less efficient. With an equal amount of rubbing, 12 ounces of 
the powder per gallon of wash ^es as efficient as 16 ounces. 
Sight ounces of powder per gallon ,rT ith the 2 man-minutes of han ; . 
rubbing pes survived by approximately 9 percent of the grubs, whereas 
with 16 ounces oer gallon the best result was a. survival of 3.15 
percent. The powders contained rotenone and extractives as follows: 
Derris 5.2 percent of rotenone and 15.5 percent of total extractives, 
cube 4.7 percent of rotenone and 21.1 percent of total extractives. 
In all, 186 cattle were used, each being handled t-ice , first for 
application of the wash and second for extraction of the grubs, which 
totaled 4,708. The cube nowder gave better results than the derris. 
^he Idaho University, College of Agriculture (144) in 1940 
recommended ground derris or code root (rotenone 3 to 5 percent) 12 
ounces, and neutral soap 2 ounces per gallon of ™ater for control of 
cattle grubs. The material should v < [just prior to each treat- 
ment end applied ^ith a stiff brush with sufficient force to enter 
