CONTROL OF TICKS 441 



tick-infested cattle in our Southern States. This has prevented the ravag- 

 ing of the nonimmune cattle of the Northern States by this disease, and 

 also has the effect of hastening the eradication of the tick in the South. 

 In South Africa quarantines are doing much to reduce the losses produced 

 by East Coast fever, but there the control of the movement of man from 

 infected to uninfected areas is also needed, though not easily enforced. 

 The infected ticks may also be shipped in hay cut on infected meadows. 



With many species of ticks which have the habit of developing in one 

 or more stages on wild animals, the question of the destruction of such 

 hosts is at once apparent. Fortunately in the case of our cattle tick 

 in the Southern States these wild animal hosts play a very unimportant 

 part in the maintenance of an infestation, and, in the instance of the 

 Rocky Mountain spotted fever tick and a number of ticks concerned in 

 transmitting East Coast fever of Africa, and other species, much can be 

 accomplished by the systematic treatment of domestic animals with little 

 attention being given to the destruction of native hosts. However, with 

 the majority of species the control, and especially eradication, can be 

 facilitated by the destruction of wild hosts. 



Since the procedure necessary to accomplish the destruction of ticks 

 must be varied according to the habits of the species concerned, the dis- 

 cussion will now be taken up by species. 



The Cattle Tick, Boophilus annulatus, and Varieties of the Species. — 

 The accomplishment of our own Department of Agriculture in the eradica- 

 tion of this tick in the Southern States is especially notable and pre- 

 sumably familiar to all. In this eradication work, which has been carried 

 on by the Bureau of Animal Industry, the dipping of cattle has been 

 relied upon almost exclusively. However, since it is both possible and 

 practical to accomplish eradication of this species by the starvation plan 

 and since this method may be utilized in a practical way, in combating 

 other species, those concerned with tick control should become familiar 

 with the principles involved. The system is dependent essentially upon the 

 proper division of the farm by fences usually placed 10 or 15 feet apart 

 to avoid infestation from one field to another, and the knowledge of the 

 time required both for ticks to complete development on the host and for 

 the seed ticks to die from starvation under different seasonal conditions 

 when proper hosts are not present for them to feed upon. By various 

 modifications of the plan the cattle and certain fields on the farms may 

 become tick free in from 4I/2 to 9 months. The entire farm will be tick 

 free in from 131^ to 15 months. 



Destruction of ticks by the use of chemicals has been practiced for 

 many years and hand dressings with various decoctions have been resorted 

 to in reducing gross infestations. Spraying is practiced where but few 

 animals are treated, but dipping must be relied upon if large numbers of 



