SUMMARY OF INSECT CONDITIONS DURING 1921. 19 



PALE WESTERN CUTWORM. 



(Porosagrotis orthogenia Morr.) 



During the season of 1921 the pale western cutworm was again 

 seriously abundant in parts f the Rocky Mountains and North- 

 Central States, the most serious damage being reported from Mon- 

 tana. Rather extensive outbreaks occurred in southwestern North 

 Dakota, and the pest was generally destructive over the winter- 

 wheat sections of eastern Colorado. 



Arthur Gibson, Dominion entomologist, reports: 



Of the cutworms the chief species reported was the pale western cutworm 

 which devastated large areas of wheat land in southern Alberta and also caused 

 some damage in certain sections of southern Saskatchewan. 



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Fig. 7. — Geographical distribution of the pale western cutworm in the United States in 

 1921 : Coarsely shaded area, very seriously infested ; finely shaded area, generally in- 

 fested ; black dots, records from literature. 



In Montana the area of general distribution extended over the 

 greater part of the State from the eastern border westward to the 

 center of Glacier Xational Park, and Jefferson County. During 

 1921 the pest destroyed from 33 to 35 per cent of the seeded area in 

 Glacier Xational Park and in Toole, Liberty, Hill, and Cascade 

 Counties, and damaged from 6 to 15 per cent of the seeded area in 

 Dawson, Prairie, and Fallon Counties in the east-central part of 

 the State and Broad Water and Jefferson Counties in the south- 

 western part. The outbreak as a whole, however, seemed less serious 

 than the outbreak of 1920. 



In Xorth Dakota the outbreak was confined to the area south of 

 Golden Valley and Oliver Counties and west of Morton and Grant 



