22 MONTANA EXPERIMENT STATION BULLETIN 457 



INSECTS INJURIOUS TO MAN AND ANIMALS 



MAN 



MOSQUITOES (Culicidae) 



Weather conditions during the last biennium have been very 

 favorable for mosquito breeding. High water and heavy rains 

 during the spring have produced ideal breeding conditions for 

 these insects, and many areas have suffered the heaviest infesta- 

 tions in years. Considerable interest has been shown in mosquito 

 control programs in most of the heavily infested areas. The State 

 Entomologist's office was consulted on mosquito control programs 

 by Glasgow, Chinook, Havre, Miles City, Malta, Harlem, and Twin 

 Bridges. Active control programs have been carried out in Glas- 

 gow, Malta, Miles City, and Great Falls, during the last two years. 

 Considerable success has been reported from these campaigns. 

 However, better results will be obtained when it is realized that 

 airplane spraying and wholesale distribution of D.D.T. sprays are 

 not the ultimate solution to the mosquito problem. The distribution 

 of D.D.T. sprays along with a well planned program of eliminating 

 mosquito breeding places, will, over a period of time, result in a 

 less expensive program and more effective control. 



LIVESTOCK 



CATTLE GRUBS (Hypoderma hovis and Hypoderma lineatum) 



Cattle grubs have been a serious pest to livestock for many 

 years. During the last few years an increased interest on the part 

 of stockmen has been shown in the subject of controlling these 

 pests. Both the early cattle grub (H. lineatum) and the late cattle 

 grub (H. hovis) are found in practically all sections of Montana. 

 During the last biennium, research has been carried on by the 

 State Entomologist's office and the Montana Agricultural Experi- 

 ment Station to determine the distribution of these two species. 

 There are some limited areas in the Gallatin Valley, the Big Hole 

 in Beaverhead County, and possibly others, where H. lineatum 

 does not occur. 



Preliminary studies are under way to determine the emerg- 

 ence dates of these grubs in different parts of the state. Observa- 

 tions show that due to differences in seasonal temperatures, 

 emergence dates may vary rather widely from year to year and 

 from region to region. In some cases such differences may be 

 observed within very narrow geographical limits. 



As was stated, the interest in cattle grub control among 

 ranchers has become more evident during the past two years and 

 in some sections the ranchers are now cooperating to carry on 

 control work on an area, rather than an individual basis. In general, 



