THE CATTLE GRUBS OR OX WARBLES 
97 
TABLE 12.—Treatment of Hypoderma lineatum and H. bovis in the backs of 
cattle, Orange County, N. Y., 1922 
ES) 
3 | 3 | Num Ne Nam Num-| 3 
S| 8 | ber of | Per Of] ber of | pe of | Se 
Bele grubs | grubs 12 
= |.6 | tubs) “not |doubt- grubs! og 
be eg se PRe9) kale |: tar 22° | Sc 
Chemicals used How applied | § Es x Ads Species 
— =] od 
- = Stage | Stage | Stage | Stage a3 
2\a seb it Bg 
A 5 3 5| 3} 4] 5, 3) 4/5 a 
= Co) 
5 |Z 3/4] 5 4 £ 
Derris, 1 part; petrolatum, | Rubbed in, 1 4| 64) 164 | O| 0} O| 0; O| 0 O} 0) 0100.00) Hypoderma 
10 parts. application. bovis and H. 
lineatum. 
Derris, 1 pound; soap, 4 | Washonback,| 9] 91) 163 12] 17 | OQ} 0} O| 75.00 Do. 
ounces; water, 1 gallon. E applica- 
ion. ; 
Derris, 1 ounce; water, 300 |____- GO ee oo 2| 43] 0} GO} 0} 0} 0/43] 0} 0} O} 0; 0} O| 00.00) H. bovis. 
ounces; soap, 514 ounces. | 
Derris extract, 1 part; wa- |___-- do__-_----_| 6] 23] 0} O| 2) 0} 0/17) 0} OF OC} 14 | 10.53 Do. 
ter, 100 parts; soap, 1 | 
art. ; | i 
Bedotorn, 1 part; petrola- | Rubbed in, 1 | 19) 206) 163 | 142 | 000 11 | 79.51) H. bovis and 
tum, 5 parts application H. lineatum:. 
Nicotine (free), 0.1 per | Washon back, 6} 100) 114 169 192 115 | 16.87) H. bovis. 
cent solution. lapplication. 
Tobacco dust, dry___-----_- Rubbed in, 1 4| 67) 13 160 1] 13 4.76 Do. 
application. 
Tobacco infusion: Tobacco | Wash on back, 3] 115} 119 156 1921 119 | 25.33 Do. 
dust, 4 pounds; lime, 1 2  applica- | | 
pound; water, 1 gallon. tions e hours | | 
apart. 
‘ Sodium hypochlorite, 2 |____- dot sas == 1} 5/0 4 2| 0 a 3] 0; 0; 0} 0; 0) 0} 40. 00 Do. 
ounces; water, 16 ounces. | | | | | | 
1 Includes all stages. Mostly fifth-stage larve, but all stages not determined. 
Several different methods were considered of computing the per- 
centage of the grubs destroyed by the various materials, but it was 
finally decided to make this computation on the basis of the number 
of grubs found alive or dead at the time of examination. 
considerable advantage to those materials which had low killing 
power, as in many cases the mature larve which were uninjured 
Furthermore, 
in the case of those substances which were very toxic, especially the 
ointments, many of those grubs recorded as gone were no doubt 
would leave the host before the results were checked. 
killed or were so weakened as never to produce adults. 
This gives 
Those 
recorded as doubtful were, for the most part, larvee which were ex- 
tracted four or five days after treatment. 
In the case of some of 
the substances it was found difficult to determine for certain in 
every case whether the grubs were dead or alive when observations 
upon them were made so soon after treatment. 
days proved to be the most satisfactory interval between treatment 
and determination of result. 
In general it may be stated that in the case of those materials 
which gave a very high percentage of mortality relatively few grubs 
were gone at the time of examination. 
be noted as exceptions to this, as they were found to facilitate the 
emergence of the grubs from the skin even though the grubs were 
dead. 
From six to eight 
Some of the ointments may 
Attention is especially directed to the results secured by the use of 
the following materials: Benzol and carbon tetrachloride when in- 
58252°—26——7 
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