EXPERIMENTS witH Nursery STock. 643 
‘The original object of the experiments conducted at Geneva was 
to throw light upon the following questions: 
(1.) Can the leaf-blight of pear, cherry, plum, and quince stocks 
and tlie powdery mildew of the apple be prevented by the use of 
_ Bordeaux mixture or ammoniacal solution of copper carbonate? 
(2.) What effect is produced upon the growth of nursery stock, 
budded, and not budded, by repeated treatments with Bordeaux 
mixture and ammoniacal solution? 
_ (8.) What effect, if any, has the variety of stock upon the scion 
or “bud” with respect: to its resistance to leaf-blight? 
While the experiments have thrown considerable light upon the 
first and second questions, the nursery was not extensive 
enough nor the soil uniform* enough to admit of any general 
-eonclusions being drawn as to the third question. Further, the 
experiment was begun so late in the season that it was not possible 
to secure stocks of uniform size, and it is doubtful if any experi- 
ments, unless made upon uniform soil, with stocks grown from 
cuttings, will settle, in a satisfactory manner, a phase of this 
problem in which there are so many variable factors. 
The various leaf diseases will now be discussed, together with 
the results of the experiments made for preventing them. The 
numerous details, of interest only to those who are pursuing 
similar studies, are given in small type at the close of the article. 
Prar-Lear Buienr (Antomosporvum maculatum, Lev.). 
This disease is perhaps the greatest obstacle to the profitable 
production of pear stocks. The principal injury is caused by a 
premature defoliation of the seedlings. .When such defoliation 
takes place early in the season, as is quite commonly the case, the 
young seedlings are forced to form a new set of leaves, presumably 
at great expense to the reserve material stored for use the coming | 
* As the experiments progressed it was plainly evident that a strip 30 feet or so wide, at the 
west end of the block, had at some previous time received fertilizers, which rendered it emi- 
nently suited to the needs of pear stocks. As no accurate record of this portion of the farm 
seems to have been kept, it was impossible to ascertain what fertilizers had been used upon the 
strip. 
