THE SCAB MITE 



307 



sheep. It travels all over the sheep's body, but it seems to have a 

 preference for the belly and under side of the neck. In piercing the 

 skin, it causes more or less irritation, and a sheep with many ticks 

 on it suffers and loses in weight and strength. It also loses wool 

 from rubbing. When the first warm days come, the ticks leave the 

 old sheep, and take to the lambs. If they are not eradicated, the 

 lambs are checked in growth and stunted. 



Ticks seldom prove fatal to the host and are such common pests 

 that flock-owners are many times unaware of the amount of injury 

 they do. By consistently following the prac- 

 tice of dipping it is possible to eradicate them 

 and there is no good excuse for having them 

 in the flock. 



The whole flock should be dipped shortly 

 after the shearing has been completed. At that 

 time the weather is usually warm and favor- 

 able for dipping; the old sheep just out of 

 their coats carry very little of the dip out 

 of the vat, and most of the ticks have gone 

 over to the lambs, making it imperative that 

 they be dipped. Ten days after the first dip- 

 ping, the whole flock should be dipped again 

 to get rid of ticks hatched from eggs that were 

 deposited before the first dipping. In the 

 autumn before the warm days have passed, 

 careful examination should be made for ticks and lice, and if any 

 are present, the whole flock should be dipped twice as before. 



When sheep are badly infested with ticks in winter, it is good 

 practice to remove the wool if warm quarters can be provided. 

 Many of the ticks are taken off with the wool and the sheep destroy 

 with their teeth most of those left on the body (Fig. 195). 



The Scab Mite (Psoroptes communis ovis). Scab mites are 

 much smaller than either ticks or lice, but if they are placed on 

 a dark background they can be seen with the naked eye. They are 

 light-colored and the females are about one-fortieth of an inch long 

 and the males one-fiftieth of an inch. 3 By piercing the skin of the 

 sheep in the act of feeding, the mite causes inflammation and irrita- 

 tion. As the mites multiply, serum oozes from the skin, and as the 



FIG. 194. Adult sheep 

 louse. (From Kentucky 

 Station Bulletin No. 143.) 



Baker, " Sheep Diseases," 1916. 



