10 FARMERS BULLETIN 798. 



hatch, but will be destroyed. It seems reasonably certain that 

 freezing temperature will destroy the vitality of the pupae. These 

 facts have an important bearing on the problem of eradication. 

 Premises or places occupied by ticky sheep may become infested, and 

 if conditions are favorable for the development of the pupae they 

 may remain infested for a period of from 45 to 50 days from the 

 time ticky sheep were removed. A seemingly safe basis of practice 

 during warm weather would be to consider all premises occupied by 

 ticky sheep as infested for a period of 60 days from the date of 

 infestation. During cold weather, when the temperature drops to 

 freezing at any period during the day or night, infested premises 

 probably would become free from infestation within a day or two, 

 except in places well protected from the cold, such as sheds and 

 stables. 



During warm weather infested corrals or inclosures should not be 

 used for clean sheep. If it is necessary to use such corrals they 

 should be cleaned and disinfected by removing all litter and manure, 

 cleaning down to a smooth surface, after which the floors and sides 

 should be sprayed with a good disinfectant. The coal-tar-creosote 

 dips diluted to double the strength recommended for dipping are 

 suitable for this purpose. The cleaning should be done carefully in 

 order that all pupae may be removed with the litter, as the disin- 

 fectant probably will not destroy the vitality of the pupcT. All litter 

 and manure from infested premises should be spread on the ground 

 and plowed under or disposed of in such manner that sheep can not 

 come in contact with it for at least 60 days. An economical and 

 effective method of disinfecting stone or wire fence corrals is to 

 scatter straw or brush over the surface of the ground and burn it. 

 If the brush or straw is dry so it will burn readily sufficient heat will 

 be produced to destroy the parasites. 



DETECTING TICKS IN THE FLOCK. 



When sheep are heavily infested with ticks they bite and scratch 

 and rub against any available object, including other members of the 

 flock. The natural position of the wool is disturbed by these eff'orts 

 to obtain relief from the intense itching; more or less wool is pulled 

 out, and the fleece may have a ragged appearance. (See fig. 7.) 



If sheep ticks are causing the trouble, they may be found by part- 

 ing the wool over the neck, breast, shoulders, belly, and thighs. 

 They are large enough to be seen readily and are of a brownish color. 

 On warm days they often may be observed crawling over the tips of 

 the wool. If ticks are present pupa^ usually will be found attached 

 to the wool fil)ers. These are seen easily with the naked eye, being 

 about one-eighth of an inch in length. Their color varies from yel- 



