670 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



impossible to get the dip to penetrate to all the ticks. Migra- 

 tion from animal to animal is slow and flocks once freed from the 

 ticks may be kept free by keeping out infested animals. Most of 

 of the ticks are removed with shearing and sometimes, if the lambs 

 do not become infested, shearing will eliminate the necessity for 

 special treatment. 



Dipping for this and other pests will be discussed more in 

 detail at the end of the chapter. 



Scab Mites* 



Scab mites attack cattle and sheep, causing a diseased con- 

 dition called scabies. Similar mites attack horses, hogs and man, 

 causing the irritation called itch or, in animals, mange. The 

 more important of these are the species affecting cattle and sheep. 



Cattle Scab or Scabies * 



The organism causing cattle scab is a minute mite, and like 

 other mites is not an insect but a member of the order Acarina. 



FIG. 590. Sheep scab-mite. (After Good, Ky. Agr. Exp. Sta.) 



The mite is a minute oval object but is visible to the unaided eye. 

 Eight short, tapering legs project from the margin of the body 



* Psoroptes communis bovis. See Marion Imes, Farmers' Bulletin 1017, 

 U. S. Dept. of Agr. 



