78 Report OF THE BOTANIST OF THE 
INTRODUCTION. 
For more than fifteen years it has been known that potato 
blight may be prevented by spraying the plants with bordeaux 
mixture. Potato spraying experiments have been made by the 
United States Department of Agriculture, by many of the ex- 
periment stations and in Europe. With but few exceptions 
these experiments have shown that the yield of potatoes may 
be considerably increased by spraying, and it is the concensus 
of opinion among experts, that, under most conditions, the 
Spraying of potatoes is a profitable operation. The results of 
these experiments and the conclusions deduced from them have 
been widely published in various publications of the United 
States Department of Agriculture, in experiment station bulle- 
tins, in the agricultural papers and through the medium of 
farmers’ institutes. 
Nevertheless, there is probably no place in the United States 
where the spraying of potatoes is generally practised by farmers 
— certainly none in New York State. In New York very few 
farmers spray their potatoes regularly. In seasons when the 
blight is epidemic, as it has been during the past season, many 
attempt to protect their potatoes by spraying, but in most cases 
only partial success is attained because the spraying is com- 
menced too late and not done thoroughly. Evidently, farmers 
in this State are not yet convinced that it pays to spray pota- 
toes regularly. As nearly as we are able to determine, the 
causes of this unbelief in the profitableness of potato spraying 
are as follows: 
(1) Blight is not destructive every season. While occasion- 
ally it nearly ruins the crop, there are other seasons when it 
does but little damage, and still others when there seems to be 
no damage whatever. Consequently, farmers look upon spray- 
ing as a matter of insurance. While they readily admit that 
there is profit in spraying in seasons when potatoes blight badly, 
they do not believe that it pays on the average. | 
(2) In many cases the spraying is not done thoroughly, and 
consequently the results are unsatisfactory. 
