CONTROL OF TICKS 



447 



horse tick requires local treatment similar to that for the spinose ear 

 tick. 



South African Ticks. — In South Africa the so-called blue tick, a 

 variety of our common cattle tick, carries bovine piroplasmosis and prob- 

 ably other diseases and may be controlled by the same procedure outlined 

 for our species. However, in South Africa this is not considered the most 



Plate XXVIII. — Spraying chicken house with oil by means of knapsack spray pump. 



(Bishopp). 



important tick parasite of live stock, since certain species of Rhipiceph- 

 alus carry the much more deadly disease, East Coast fever. Since the 

 innnature stages of the brown tick (R. appendiculatus ) , the principal 

 agent in the dissemination of the disease, become engorged and leave 

 tlie host in three days or less, it becomes necessary to dip at very short 

 intervals to prevent the escape of specimens which may infect other 

 animals. The larvae or nymphs which engorge on cattle infected with 

 East Coast fever are the only direct source of propagation of the disease 

 in otlier animals, hence the main attack must be directed against them. 



