October, '12] 



MOORE: AFRICAN TICK PROBLEM 



381 



would fall off, as stated above. From the facts given, however, it 

 will be seen that within four weeks the larvae and nymphse which 

 have dropped from the cattle when thej^ were first moved into C will 

 have moulted to the succeeding stages and be again found on the 

 cattle. 



Therefore it is advisable to move the cattle at the end of 18 days 

 to a new plot D so that the ticks which have dropped off in C will 

 not have had time to moult and again seek the host. In D the 

 remainder of the ticks on the animals will drop off and in 18 days 

 the animals tick-free could be turned into A. B, C, and D could be 

 closed against cattle for 14 to 16 months and the farm thus freed of 

 ticks. This method in theory would rid the farm of all the ticks which 

 are known to transmit diseases to oxen, horses, sheep and goats. 



In practice however the starvation of ticks is not so easy, due to 

 the number of wild animals which will act as hosts to the ticks, thus 

 carrying them over the starvation period. 



The following table of the common ticks, which will attach them- 

 selves to some of the common wild animals, will show how easily the 

 tick can be carried over the "starvation period": — 



COMMON AFRICAN TICKS AND THEIR WILD HOSTS 



This table compiled from the work of C. W. Howard, shows that of 

 those ticks which transmit disease but two species do not find a host 

 on the wild animals. In an actual trial of the starvation method car- 

 ried out by H, E. Laws in the East London district, the results obtained 

 are very nearlj'- what one would expect from the above. A portion 

 of a farm was closed to all stock in ]\Iay 1908. In February, 1911, 

 ten oxen were driven to the gate of the enclosed farm, and after all 

 the ticks which could be found were picked off, they were thoroughly 

 sprayed with a mixture of kerosene and water containing 25 percent 



