THE SHEEP TICK AND ITS ERADICATION BY 

 DIPPING. 



Page. 



Distribution and economic importance 3 



Life history 4 



Nature arrcl habits 7 



Spread 9 



Fage. 



Detecting ticks in the flock 10 



Eradicating the licks by dipping 11 



Dipping plants 23 



Construction of dipping plants 29 



DISTRIBUTION AND ECONOMIC IMPORTANCE. 



The sheep tick {Mclophagus ovinus) is not a true tick but a ■wing- 

 less parasitic fly which passes the various stages of its life on the 

 sheep. In many of the English-speaking countries it is known as the 

 '' ked " and is sometimes called the '' louse fly " from its habit of liv- 

 ing in the wool like a louse, but among the sheep growers of this 

 country it is known as the sheep tick. It is widely distributed in 

 many of the sheep-growing countries of the world, including the 

 United States where it is known to occur in practically all of the 

 States where sheep are kept. It is most preA'alent, however, in the 

 western range States where sheep are herded in large flocks. The 

 northern two-thirds of the range country, or that part known as the 

 Northwest, is the most heavily infested. 



For a number of years it had been the custom in the majority of 

 the principal sheep-growing States to dip the flocks regularly for 

 scab. Such dipping evidently checked the spread of sheep ticks 

 also, but as scab has been eradicated in many of the States com- 

 pulsory general dipping for scab was discontinued in such areas, 

 and especially in the Northwest. In the meantime the ticks spread 

 rapidly and became prevalent in many of the flocks to such an extent 

 that in some of the States compulsory general dipping was resumed 

 in order to eradicate them. The sheep owners in some of the South- 

 Avestern States have continued to dip their flocks more or less regu- 

 larly each season and consequently the ticks are not so plentiful in 

 those areas. However, they are gaining a foothold in many of the 

 flocks in this section, and conditions indicate that they may' become 

 a source of considerable loss if dipping is discontinued before they 

 are eradicated. 



3 



