91 
ties. As the early varieties were harvested July 15, they were less 
exposed to injury than the fruit on the sprayed trees, which was 
harvested from September 16 to 20. This is a difference, however, 
which tends to diminish the contrast between the sprayed and un- 
sprayed trees, and thus to show, if anything, a smaller result from 
spraying than was actually obtained. 
The Winesap and Ben Davis trees, 119 in number, were sprayed 
eight times in succession, and the fruit from 4 of these trees (3 Ben 
Davis and i Winesap) was picked and examined with reference to 
curculio injuries. The unsprayed orchard used as a check on this 
experiment contained 145 trees, all Sops of Wine and other early 
varieties except 4 Ben Davis (see Section 4, Columns i, 2, and 3). 
The fruit from 9 of these check trees was examined July 15, all 
Sops of Wine except i Ben Davis. These yielded 3,463 apples, 
making 14^ bushels, ecjual to 1,540 apples, or 6.44 bushels from 4 
trees (Columns 4 and. 5), while the 4 trees sprayed, the apples from 
which were picked September 16 to 20, yielded 3,198 apples, mak- 
ing 24^ bushels. These differences in number of apples and bulk 
of yield can not properly be taken into account in this case, because 
both flight well be attributable, at least in part, to the difference in 
variety between the sprayed and the check trees from which the 
fruit was counted. 
The curculio injuries on the 9 unsprayed trees had affected an 
average of 91 per cent, of the apples (Column 6), and on the 4 
sprayed trees, an average of 18J/2 per cent., from which it appears 
(Section 8, Column 7) that 80 per cent, of the apples which might 
have been injured by curculios if no treatment had been applied, 
had been saved from such injury by the arsenical spray. Here 
~again it is possible that a varietal difference in susceptibility to 
curculio injury may have affected these percentages. 
Cost of th^ Operation. 
The reader will be especially interested to know the cost of our 
operation, figured in terms practical to the fruit grower. I have 
worked this out in full detail for the 292 trees sprayed in these 
orchards, including the actual price of materials purchased in the 
ordinary markets, the amount of materials used, and the labor of 
appHcation at $1.25 a day and board for men employed, and $2.50 
a day and feed for a team. Without entering into details, unnec- 
essary for my purpose, I find that the total cost ranges from 4 to 
5 cents per tree for each treatment, or 17 cents per tree for the four 
treatments found most effective. Of this only 2 cents was for ma- 
terials, the remaining 15 cents being for labor of man and beast, 
much of which, in many cases, the fruit grower might supply with- 
out special outlay. 
