MONTANA INSECT PESTS 1945-1946 11 



several years were reported from Glacier, Toole, Pondera, Liberty, 

 and Chouteau. In the eastern part of the State the infested area 

 appears to be considerably reduced. Light to severe infestations 

 are expected in Richland, Dawson, McCone, Prairie, Custer, Rose- 

 bud, Treasure, Powder River, Carter, Big Horn, Yellowstone, and 

 Stillwater counties, with the heaviest populations being in Custer, 

 Powder River, Rosebud, Treasure, and Big Horn. 



Although weather conditions prevented a detailed survey in 

 the western part of the State, it appears that light to threatening 

 infestations are likely to occur in eastern Sanders, northern Lake, 

 and southwestern Flathead counties. 



Indications are that the infested area will not be so extensive, 

 in the State as a whole, as it was in 1946 and for several years 

 previous to 1946. However, populations will possibly be more con- 

 centrated and heavier than in the last five years, and serious local 

 damage may result. 



OTHER IMPORTANT INSECT PESTS, 1945-46 



MORMON CRICKET (Anahrus simplex) . — Populations of this 

 insect during the past two years have been light and not of econ- 

 omic importance and control work has not been necessary. 



Severe outbreaks of Mormon crickets have occurred in Nevada, 

 Idaho, Washington, and Oregon this year, and it was feared that 

 heavy infestations in these states might be an indication that a 

 "build-up" could be expected in Montana. A survey was made in 

 areas which were heavily infested from 1934 to 1942. This survey 

 included sections of the following counties: Big Horn, Yellowstone, 

 Carbon, Custer, Rosebud, Sanders, Lake, Chouteau, Cascade, Fer- 

 gus, and Judith Basin. Widely scattered crickets were found in 

 these areas, but no bands or heavy populations were observed. It 

 appears that there has been a slight increase in the number this 

 year, especially in the areas in Big Horn, Rosebud, and Powder 

 River counties. 



All potential cricket areas in the State will be watched closely 

 in an effort to control small incipient outbreaks before they be- 

 come severe and migrations into crops occur. 



FIELD CRICKET (Gryllus assimiUs) . — An outbreak of field 

 crickets was observed causing considerable damage to seed alfalfa 

 in Big Horn County in the vicinity of Hardin. The fields which were 

 inspected had an estimated average of 20 crickets to the square 

 yard. The insects were feeding on all parts of the plants and were 

 especially injurious to the seed pods and blossoms. 



Egg deposition was extremely heavy and it is likely that a 

 severe infestation will occur again next year. 



