﻿THE CATTLE GRUBS OR OX WARBLES 



97 



Table 12. — Treatment of Hypoderma Uneatum and H. bovis in the backs of 

 cattle, Orange County, N. Y., 1922 



Chemicals used 



Derris, 1 part; petrolatum, 



10 parts. 



Derris, 1 pound; soap, 4 

 ounces; water, 1 gallon. 



Derris, 1 ounce; water, 300 

 ounces; soap, 53^ ounces. 



Derris extract, 1 part; wa- 

 ter, 100 parts; soap, 1 

 part. 



Iodoform, 1 part; petrola- 

 tum, 5 parts 



Nicotine (free), 0.1 per 

 cent solution. 



Tobacco dust, dry 



Tobacco infusion: Tobacco 

 dust, 4 pounds; lime, 1 

 pound; water, 1 gallon. 



Sodium hypochlorite, 2 

 ounces; water, 16 ounces. 



How applied 



Rubbed in, 1 

 application. 



Wash on back, 

 1 applica- 

 tion. 



...-do 



do 



Rubbed in, 1 



application 



Wash on back, 



1 application. 

 Rubbed in, 1 



application. 

 Wash on back, 



2 applica- 

 tions 24 hours 



apart. 

 do 



Num- 

 ber of 

 grubs 

 kiUed 



3 4 5 



i64 

 163 



163 

 114 



1 3 

 119 



Num- 

 ber of 

 grubs 

 not 

 kiUed 



Stage 



3 4 5 



142 

 169 

 160 

 156 



Num- 

 ber of 

 grubs 

 doubt- 

 ful 



Stage 



3 4 5 





 12 

 11 

 121 



Num- 

 ber of 

 grubs 

 gone 



Stage 



3 4 5 







14 



11 

 115 

 13 

 119 





o o 



100.00 



75.00 



00.00 

 10.53 



79.51 

 16.87 

 4.76 

 25.33 



Species 



Hypoderma 

 bovis and H. 

 lineatum. 

 Do. 



H. bovis. 

 Do. 



H. bovis and 

 H. lineatum. 

 H. bovis. 



Do. 



Do. 



Do. 



1 Includes all stages. Mostly fifth-stage larvae, 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. This gives 

 considerable advantage to those materials which had low killing 

 power, as in many cases the mature larvse which were uninjured 

 would leave the host before the results were checked. Furthermore, 

 in the case of those substances which were very toxic, especially the 

 ointments, many of those grubs recorded as gone were no doubt 

 killed or were so weakened as never to produce adults. Those 

 recorded as doubtful were, for the most part, larvae which were ex- 

 tracted four or five days after treatment. In the case of some of 

 the .sub.stances 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. From six to eight 

 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. Some of the ointments may 

 be noted as exceptions to this, as they were found to facilitate the 

 emergence of the grubs from the skin even though the grubs Avere 

 dead. 



Attention is es[)ecially directed to the results secured ))y the use of 

 the following materials: Benzol and carbon tetracldoride when in- 



58252"— 26 7 



