changes resulted in greater 

 populations of cattle and deer, as 

 well improved tick habitat. Because 

 of these changes, tick survival was 

 enhanced. 



dipped. Dipping is generally 

 considered the most convenient, 

 efficient, and economical method of 

 killing ticks on large numbers of 

 cattle. 



The normal hosts for B^ annulatus in 

 the United States are cattle, horses, 

 and occasionally sheep and goats. 

 Boophilus micro pi us infests cattle, 

 horses, goats, sheep and occasionally 

 deer. Hvimans can influence the 

 choice of hosts. Exotic animals 

 which may be normal hosts for 

 Boophilus ticks in their native 

 country are sometimes introduced into 

 the United -States. This occurred 

 with the introduction of nilgai, an 

 antelope-like game animal , into the 

 endemic tick area of south Texas. 



Animals that do not normally 

 associate, or do so only under 

 special conditions, may be forced 

 into sharing land area so that they 

 become a common group composed of 

 several species of animals. In such 

 situations, surveillance programs 

 must be developed to include all 

 species which may be a threat to the 

 tick eradication program. 

 Recognition of changing epidemiologic 

 factors must lead to the development 

 of new surveillance methods and 

 policies. The program must remain 

 flexible and receptive to new 

 concepts if total eradication is to 

 be acheived and maintained. 



Dipping Vat Management , 

 Resistance, and Tick Eradication 



The objective of dipping livestock 

 is to kill parasites, normally 

 external parasites, without causing 

 harm or death to the animal being 



Dipping vats provide an efficient 

 method of pesticide application in 

 that the pesticide is, confined which 

 eliminates the problem of drifting 

 sprays and exposes only the target 

 animal to the pesticide. A drain 

 pen functions as a recovery unit 

 which returns excess dip carried out 

 by the animal to the vat, thus 

 protecting the environment and 

 reducing the cost through better 

 chemical utilization. 



It is very important to use approved 

 pesticides at the recommended 

 concentration. Lethal concentration 

 percentage (LC percent) have been 

 established for each pesticide used 

 in the official USDA tick 

 eradication program. The minimum 

 acceptable concentration of 

 pesticide should be at least the 

 LC . The LCgg is a 

 mathematical estimate based on 

 trials performed under controlled 

 laboratory conditions in which 99 

 percent of the target species is 

 killed. Years of field experience 

 have documented the need to 

 establish program pesticides that 



are above the LC, 



9* 



This extra 



It 



pesticide concentration may be 

 termed the "eradication factor", 

 is important to use pesticides at 

 greater than the LCqq in order to 

 avoid the development of resistance. 

 "Chemicals have been valueless 

 following the development of 

 resistance." There appears to be 



Nolan, James and Roulston, 

 W. J., Acaricide Resistance as a 

 Factor in the Management of Acari 

 of Medical and Veterinary 



Importance, IN: Recent Advances in 

 Acarology , Volume II, Edited by J. 

 G. Rodriguez, Academic Press, New 

 York, San Francisco, London, 1979, p. 12, 



