New YorK AGRICULTURAL EXPERIMENT STATION. 79 
(3) Few farmers who spray potatoes know accurately how 
much they have increased the yield by spraying. Usually no 
portion of the field is left unsprayed; hence there is no basis for 
comparison except the unsprayed fields of neighbors. Even 
where a few rows are left unsprayed for comparison the differ- 
ence in yield is usually guessed at and rarely determined ac- 
curately by weight or measurement. 
(4) Often there is a lack of confidence in the results obtained 
at experiment stations. Many persons believe that in exper'- 
ments made at the stations the potatoes have been given an 
extra chance, and that it is impossible to duplicate the results 
in ordinary farm practice. 
DETAILS OF THE EXPERIMENTS. 
OBJECTS. 
The chief object of the experiments herein reported was to 
ascertain how much the vield may be increased, on the average, 
by spraying potatoes in New York State. With this point 
definitely determined, it will be considerably easier to give a 
correct answer to the question, Does it pay to spray potatoes 
reguarly? Since the profit to be derived from spraying de- 
pends upon the relation existing between the expense of the 
treatment and the value of the increase in yield due to the 
treatment, the ideal experiment would be one which takes both 
of these factors into account; but in order that the test might 
be a fair one, so far as the expense is concerned, it would be 
necessary to have several acres included in the experiment. 
This would have made more work than it was deemed advisable 
to undertake, and so it was decided to attempt only the solu- 
tion of the simpler but more important part of the problem; 
namely, the average increase in yield. We consider the ques- 
tion of increase in yield more important for the reason that it 
varies greatly from year to year, whereas the expense of spray- 
ing varies but little in different seasons. 
It is possible that next season the Station will undertake 
some supplementary experiments especially designed to deter- 
mine the expense of spraying. 
