22 MONTANA EXPERIMENT STATION BULLETIN 526 



Elsewhere in the state a few towns are carrying on mosquito 

 control programs and the Office of the State Entomologist furnishes 

 technical information wherever it is requested. An informational bulle- 

 tin relative to mosquito control has been prepared and distributed. 



CATTLE GRUBS (Hypoderma lineatum, H. bovis) 



During 1955 this office, in cooperation with the Montana Agri- 

 cultural Experiment Station, conducted tests with phenothiazine fed 

 with salt mixtures to cattle for cattle grub control. Although a reduc- 

 tion in early grubs was evident, no discernible difference was found 

 in late grub populations which appear to be harder to control. New 

 compounds based on this internal medication principle will be tried 

 if and when they are released for experimental use. 



CATTLE LICE (Mallophaga and Anoplura) 



During the winter of 1954-55 an experiment conducted to evaluate 

 the efficiency of cable-type back rubbers for louse control was carried 

 on by this office. It is apparent that this method will control lice 

 if the back rubbers are properly constructed and used. In those cases 

 where cattle are reluctant to use these devices, spraying or dipping 

 is still the best method of control. A publication discussing the species 

 of lice, life histories, pros and cons of various control methods, and 

 other technical information is now in preparation. 



SHEEP KEDS (Melophagus ovinus) 



Sheep keds are present state wide wherever sheep are raised. A 

 rotenone spray or dieldrin dust appears best for control. 



WOOD TICKS (Dermacentor andersoni) 



During 1955 and 1956 bands of sheep trailing to shearing pens 

 have become heavily infested with wood ticks. In some cases paralysis 

 and death have resulted. As of the present time no practical means 

 of control have been developed. It is thought that perhaps an under- 

 belly spray of fairly high concentrate dieldrin may be of value. 



HORN FLIES (Siphona irritans) 



Only moderate populations of these pests were observed during 

 the biennium. 



DOG LICE (Linognathus setosus) 



Only one case of dog lice was brought to our attention during 

 the biennium. A dog in Pondera County was heavily infested but 

 responded readily to treatment. 



