224 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
common with pear trees that were seriously affected by the psylla. 
The number of. peach trees that died in this way was compara- 
tively small. 
In most cases some growth started in the trees, as it was able 
to do with the starch in the branches, but when this became 
exhausted in May or June and plant food was unable to come up 
from the roots in sufficient quantities the leaves.dropped and the 
trees perished. 
With some trees a limited amount of plant food could be forced 
up into the branches and here the growth continued until July 
or August when a few days of continuous dry, warm weather 
would cause the demand for more moisture than could be forced 
up through the injured tissues of the trunk and the tree would 
die. 
The dying of the trees at such unusual and irregular times gave 
rise to much alarm among the fruit growers in some localities. It 
was feared that a virulent attack of the “ yellows” had broken 
out or some new and serious disease had become prevalent. 
Upon injured trees that did survive, the most striking effect of 
the damage was noticeable in the foliage. In proportion to the 
degree of damage the leaves were under normal size and not of 
their natural color. On some of the trees they were about one- 
third size, and the color was usually a pale green, though occa- 
sionally tinges of red not unlike that produced by the leaf curl 
disease were noticeabie. This effect was so striking as to be con- 
spicuous from a long distance. The effect was very noticeadie in 
the amount of new growth made during the growing season. In 
some instances this did not exceed a few inches in length, and 
from this it varied up to practically the normal amount. 
Fruit that did mature on injured trees was under normal size 
for the variety. This effect was especially noticeable or peyches 
and pears. E: 
ENVIRONMENT AS RELATED TO INJURY. 
Altitude, air drainage and conditions of the soil had a very im- 
portant bearing upon the severity of the injury. The advan- 
tages of a high altitude were best shown in some of the peach 
orchards in the Hudson Valley.. Orchards that were located on 
the highest sites were injured the least of any, and many of them 
bore a fairly good crop of fruit. Those located on the low sites 
