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Hoenig ( 140 ) in 1936 tested four derris preparations for marble 
control on cattle. One washing with a 4— percent solution of P?n- 
derrah-i.ierck killed 83 percent of the larvae. A single -ashing with 
a. 5-percent Abdassol solution resulted in the death of 38.8 percent, 
whereas one washing with a 10-percent solution produced °5.6 percent 
of healing. Abdassol was the most .satisfactory agent "because of its 
ease of amplication (foaming readily), its cheapness, great effective- 
ness, and complete hermlessness to the animals. ■ A single washing i 'ith 
8: •"io--percent Derrisol-Bongsn solution gave a kill of 91.5 percent. 
One, washing ^ith a 4-percent Derrilavol solution resulted in a 75.3 
percent kill of the larvae, which the ^uthor did not consider 
sufficientlv good. 
The Department of Agriculture of the Irish Fr.ee State ( 148 ) in 
1936 reported experiments made in' Ireland for the control of Hyp ode ma 
larvae ^ith Polvo and Paragrad, Polvo reouires the addition of a 
spreader for successful application. The spreader . (soft soep) is dis- 
solved in hot water and mixed with the Polvo to form a paste, which 
is then reduced to the reouired strength by the addition of water. 
Paragrad has a spreader' incorporated in it, and all that is necessary 
is •to. mix the ponder - with water to form a paste and reduce it to the 
reouired strength by the addition of water. The preparation is then 
read:-- for use. The dressings were used .at the following strengths: 
Polvo 1/2- pound, soft soap 1/4 pound, water 1 imperial gallon; Paragrad 
1/2 pound, water 1' imperial gallon. The dates, o'f- the first ^pplic--- tion 
varied at the different centers, depending on. the maturity of the grubs 
but, generell\ r speaking, the first dressing was applied; about the last 
-^eek of Kerch and repeated at intervals of a. month. Three applications, 
and in some cases only t r- o, were generally sufficient for the complete 
destruction of all grubs. The number of animals treated- ^es 965. The 
total number of grubs that appeared dxiring the. tests was 13,891, an 
average of 14.4 per animal. On the cattle treated with Polvo a total 
of 5,805 warbles developed, and 6,701 or 98 percent were killed. On 
the cattle dressed with Paragrad 7,086 ^arbles appeared and 6,868, 
or 97 percent, were killed. From the above results, there is apparently 
little choioe between Polvo end Paragrad. Most of the instructors 
in these trials favored Paragrad because it is easier to prepare, 
needing only the addition of cold water, whereas with Polvo both soft 
'soap and hot ^eter are required. 
The Kolonieal Instituut'of Amsterdam ( 162 ) in lg^ reported that, 
in general, the various stages of Dintera are but little sensitive to 
derris. The larvae of the warble fly is a favorable exception. Finely 
ground derris root seems to be a powerful, control measure against this 
pest and is not injurious to domestic animals or man. 
According to Yen der Laan ( 165 ) in 1936, the larvae "-ere sensitive 
to derris. 
Maheux ( 194 ) in 1936 published directions for the treatment of 
warbly cattle in Quebec with or -priet'ry rote^.one preparations. 
