New York AGRICULTURAL EXPERIMENT STATION. 121 
follows: (1) After the buds break, but before the blossoms open; 
(2) immediately after blossoming; (3) from ten to fourteen days 
after the second treatment. This is still the standard treatment. 
Another result of the experiments in 1894 was a considerable addi- 
tion to our knowledge of the injury to apples (russeting of the 
fruit) which sometimes results from the use of bordeaux mixture. 
Taking advantage of the opportunity offered by the large number 
of varieties in the Station orchard, the different varieties of apples 
were classified according to their susceptibility to spray injury. 
Further investigation of spray injury was made in 1902? when the 
yellowing and dropping of apple leaves were so common in western 
New York as to cause widespread alarm among apple growers. 
Although it was proven that much of the trouble was caused by 
spraying, orchardists were advised, nevertheless, not to discontinue 
spraying because, notwithstanding the injury, spraying usually did 
more good than harm. 
However, in 1905, when spray injury was more common than 
ever, many fruit growers began to think seriously of giving up the 
spraying of apples. This idea became so prevalent that it seemed 
_ necessary for the Station to go yet more deeply into the matter in 
order to discover if possible the exact cause of spray injury and a 
way to prevent it. This investigation was conducted in 1906 by the 
Horticultural Department. Some of the principal facts definitely 
determined were the following: 
(1) Bordeaux mixture, no matter how carefully prepared, may 
cause injury to foliage and fruit. 
_ (2) It is the copper sulphate, and not the lime, which is the in- 
jurious ingredient and the greater the amount of copper sulphate 
the greater the injury. 
(3) Wet weather favors the production of the injury. 
(4) An excess of lime in the bordeaux does not prevent spray 
injury nor even lessen it materially. 
In the light of these and other established facts the following 
practical suggestions for spraying were made: “Use less copper 
sulphate ; give the 3-3-50 formula for bordeaux mixture a thorough 
trial. Spray in moderation; spray to cover the foliage and fruit 
with a thin film and yet not have the trees drip heavily. So far as 
possible the bordeaux mixture should be used only in dry weather. 
Use equal amounts of lime and copper sulphate. Some varieties of 
*® Bul. 220 (1902); same in Rpt. 21:67—75. 
* Bul. 287. (1907). 
