SOME PESTS OF OHIO SHEEP 69 



tion of lice did not result from this test. Twenty-five days after 

 treatment seven lice were found on three out of fifteen sheep ex- 

 amined. On most of the fifteen many dead lice were found. 



Sodium fluorid appears to be very destructive to lice without 

 producing any ill effects upon the host animals. No skin irritation 

 or injury to the condition of the wool was observed. In dusting 

 there was occasionally some temporary irritation of the air pass- 

 ages, as evidenced by sneezing. 



It is said that if some of the sodium fluorid in the dust f orm 

 reaches the body of the operator and if allowed to remain for a 

 number of hours, as might be the case in dusting many animals, 

 local irritation and burning may occur on tender portions of the 

 skin. This effect was not experienced by the writer nor helpers. 

 No special precaution was taken, but winter clothing and extra 

 overalls may have afforded the necessary protection. During the 

 operation some dust floats in the air which causes irritation of the 

 throat and nose of the operator. This, although it caused con- 

 siderable sneezing, proved only an incidental inconvenience. It 

 may be prevented by keeping pieces of wet cloth over the nostrils 

 and mouth, or by the use of a dust guard. 



Summary. — Dipping with an effective liquid parasiticide is the 

 most satisfactory remedy for external parasites. 



Dipping is not advisable in the winter. 



Powder insecticides give promise of being satisfactory for 

 winter use. 



Sodium fluorid was used in a test conducted at the Ohio Agri- 

 cultural Experiment Station; 104 sheep were used in the test. 

 The powder was blown into the wool by means of a hand powder 

 gun. 



The barrel and plunger type of powder gun proved the more 

 satisfactory. From 10 to 15 minutes was required to treat each 

 sheep using about six-tenths of an ounce of powder to each animal 

 treated. 



Sodium fluorid kills the lice without producing a detrimental 

 effect upon host animals or operator. 



SHEEP FOOT LOUSE 



Haematopinus pedalis Osborn 



Injury. — This louse differs from the other lice of sheep and 

 goats in size, shape and character of the mouth parts. The latter 

 are adapted for piercing the skin and sucking the blood of the host 

 animal ; hence, should the lice occur in abundance upon an animal, 

 the injury no doubt would be more severe than that due to lice that 

 do not puncture the skin. 



