102 REPORT OF THE BOUANIST OF THE 
increased the yield 984 bushels per acre. Had these same three 
Sprayings been applied to fields near Geneva which yielded only 
100 bushels per acre without spraying, it is unlikely that the yield 
would have been increased as much as 983 bushels per acre; but 
just how large an increase might be expected in such a case is 
not clear’. Of course much depends on the cause of the low 
yield. If it were chiefly due to the ravages of insects or blight 
the case would be quite different from what it would be if there 
were errors in culture or a lack of fertility. Spraying cannot be 
expected to correct errors in culture or take the place of fertility. 
With the ravages of blight and insects the same, it seems prob- 
able that the maximum benefit from spraying is to be obtained 
in potato fields in which all other conditions are most favorable 
to a large yield. 
While an increase of 984 bushels per acre is to be considered 
an excellent return for three sprayings, the amount is not as 
great as it might have been had the blight been as severe in the 
experiment field as it was in many other fields around Geneva. 
In some respects the conditions for getting large returns were 
exceptionally good in the experiment, but on the whole it seems 
as if up-to-date potato growers, who employ correct cultural 
methods, fertilize liberally and spray properly, should have done 
equally well during the past season. 
DOES IT PAY TO SPRAY POTATOES? 
To give a positive answer to this question would be to antici- 
pate the results of the long series of spraying experiments just 
_— 
10The best information on this subject available is furnished by a farmer living about five 
miles northwest of Geneva. He sprayed 12 acres of potatoes three times with a power sprayer 
which sprayed five rows at a’time with one nozzle per row. One row through the center of 
the field was left unsprayed. This row was dug separately and the yield carefully measured. 
The same was done with an adjacent sprayed row. It was found that the sprayed row out- 
yielded the unsprayed row by a trifle more than three bushels. Since sixteen rows were 
required to make an acre, the increase in yield amounted to over 48 bushels per acre. The 
yield on the unsprayed row was at the rate of 110 bushels per acre and on the remainder of 
the field about 160 bushels per acre. He estimates that on the twelve acres spraying increased 
the yield by nearly 600 bushels of potatoes having a value of $300. Of this sum at least $235 
was clear profit. 
In this case the spraying could not have been thoroughly done, and consequently the results 
are not strictly comparable with those obtained in the experiment on the Station farm; but 
they show what can be done by farmers under average conditions. Unquestionably, 
there are hundreds of farmers in central and western New York who could have made $20 
per acre net profit by spraying their potatoes last season. 
