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(i MOXTANA EXPERIMENT STATION Bui. 139 



greater part of Montana owing" to the serious damage which it has 

 inflicted upon cereals and other crops. The following table of losses 

 by percentages of total seeded areas in the various counties for 

 which we had definite information during the season of 1920 will 

 indicate the seriousness of this pest : 



Hill County 25.1 per cent 



Liberty County 47.1 



Cascade County 35. 



Jefferson County 36.01 



Broadwater County 23.9 



Chouteau County 30.7 



Phillips County 16.9 



Teton County 29. 



Average 30.1 " " 



\\ hen the counties of Pondera, Glacier, Blaine, Judith Basin, 

 Lewis and Clark, and part of Park County, where it is estimated 

 almost as large a percentage was lost, are included with the above 

 counties, fully one-fourth of the total grain-producing acreage of 

 the state is represented. At $12 per acre, which is the average value 

 i f farm crops over that territory, there was a money loss of 

 $2,600,000. Then, considering that the pale western cutworm 

 occurs in practically every other county of the state east of the 

 continental divide besides those already mentioned, where an average 

 loss of from 2 per cent to 5 per cent was inflicted, the total loss 

 amounts to well above $3,000,000 for the one year 1920. 



To show perhaps a little more clearly what this cutworm has 

 been doing, one hundred fields personally inspected during the sum- 

 mer showed a loss of 2,437 acres out of a total of 6,844 in 1919, and 

 in 1920 a loss of 3,382 acres out of 6,844, or 35.7 per cent in 1919 

 and 49.4 per cent in 1920. Mr. George O. Sanford, manager of the 

 Sun River Irrigation Project, has stated to us that of the 15,300 

 acres seeded to crop on the Greenfield Bench in 1920, 7,345 acres 

 was a total loss and that some damage was done to the remainder. 

 Using the figures he has given for the average yields on the unde- 

 stroyed acreage — wheat 11.5 bushels, oats 20.86 bushels, and flax 

 6.31 bushels — the average value of the principal farm crops of that 

 section was at least $15 per acre. Accordingly, using that as a fair 

 valuation per acre of the crops destroyed, the pale western cutworm 



