336 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
were no blossoms on this plot, and the foliage was so severely eaten as 
to render the hay almost valueless. Growth was not resumed until 
three weeks later than on the sprayed field adjoining. Relative stages 
of development were maintained on all plots throughout the period of 
growth of the second crop which was cut August 15th. 
Hay Weights 
Plot No. 
First Crop 
• > 
Second Crop 
Total 
1 
5957 lbs. 
5313 lbs. 
11270 
5 
• 
4761 lbs. 
6 
4799 lbs. 
4135 lbs. 
8934 
All the first and second cutting hay on each plot was weighed with the 
exception of second crop hay on Plot No. 5 as noted above. Third crop 
hay was not weighed because of weather conditions unfavorable to 
obtaining accurate data. 
Cost of Two Spray Applications per Year and 
vSaving Resulting 
It has been proven by practical field work that under average field 
conditions a traction spray machine will care for 200 acres of alfalfa 
per year, and that with average care a machine should operate satis¬ 
factorily for at least five }^ears. On this basis the following calculations 
are made : 
Cost of Spray machine complete with spray bar and filling pump.$300.00 
Calcium arsenate for 1000 acres, 4 lbs., per acre per year for 5 years, 4000 lbs. 
@ 20 c... 800.00 
Repairs for machine, estimated at $20.00 per year. 100.00 
Labor, man and team, 70 days, 14 days per year for 5 years, @ $6.00 per day. 420.00 
Total cost of spraying 1000 acres twice, 200 acres per year for 5 years.$1620.00 
Cost of spraying one acre twice, or cost per year.$ 1.62 
A fair valuation to the farmer for alfalfa hay in Idaho over a period 
of years is $8.00 per ton. From weight tabulations above it will be 
noted that the gain in hay per acre as a result of spraying was 2336 
pounds. From these figures the net saving is derived: 
Sale value 2336 pounds hay @ $8.00 per ton, or gross saving per acre. $9.34 
Cost of spraying, per acre. 1.62 
Net saving from spraying, per acre. $7.72 
The loss from weevil is often much greater than occurred this season 
on the experimental check plot, and saving from spraying is correspond- 
