32 THE ROCKY MOUNTAIN SPOTTED FEVER TICK. 
Texas and New Mexico the Cayenne tick (Amblyomma cajennense 
Fab.), is a common pest of man. 
PRACTICAL CONTROL OR ERADICATION OF THE SPOTTED-FEVER 
TICK. 
In 1909 Dr. Ricketts suggested, in a general way, a plan for the 
practical eradication of spotted fever from the Bitter Root Valley 
by a campaign against the ticks. Tt became evident to Dr. Ricketts 
as the result of his work on spotted fever that the only method of 
controlling the disease was by destroying the natural agency of 
transmission. The work of the Bureau of Entomology in cooperation 
with the Montana Agricultural College and the Biological Survey in 
obtaining exact information about the life history and hosts of the 
tick has served to elaborate upon the suggestions made by Dr. 
Ricketts and to make it possible to lay down definite plans that 
should he followed. 
It has been pointed cut in this bulletin that the plan of eradica- 
tion, which is dependent upon a knowledge of the tick, is entirely 
feasible and economical. The question now is whether the loss of 
25 or more human lives per year in the Bitter Reot Valley, the 
onus placed upon the development of the valley by the presence 
of spotted fever, and the danger of the spread of the virulent strain 
of spotted fever to other regions are not of sufficient importance to 
justify the small cost that the work will entail. A considerable por- 
tion of this cost would be offset by the improved condition of the 
live stock which would result from the destruction of the ticks as 
well as of certain other parasites. 
CONDITIONS FAVORING CONTROL. 
Tt will be understood from the discussion of the life history of the 
spotted-fever tick that several facts will assist greatly in an attack 
against it. Among these are the following: 
(1) The vast majority of fever ticks which develop to the adult 
stage in the Bitter Root Valley do so upon horses and cattle, although 
small numbers develop upon sheep and a very few upon dogs. The 
only other domestic animal of any importance in the Bitter Root 
Vailey is the hog. Although no fever ticks have ever been found 
upon hogs in the valley the adult form was taken in considerable 
numbers on that host on one occasion in Wyoming. It is therefore 
evident that under some conditions the hog is to be looked upon as 
an agency for the breeding of the ticks. The danger on this score, 
however, is exceedingly remote on account of the methed of manage- 
ment of hogs in the valley. In the first place the number of these 
animals is not large. In the second place they are not allowed to 
roam at large but are confined to pens or small inclosures where the 
chances of their picking up fever ticks are very small. If hogs were © 
