New York AGRICULTURAL EXPERIMENT STATION. 67 
the rupturing of the epidermis on some blisters while it re- 
mained intact on others, and the formation of irregular, dead. 
brown spots, were all practically the same as with apple leaves, 
the principal difference being that on the quince the majority of 
the blisters broke early in the season and formed dead spots. 
Later, portions of the dead tissue fell away, leaving ragged 
holes in the leaf which would have been difficult to account for 
by one unfamiliar with the circumstances. 
Because of the close relationship existing between the apple 
and the pear it was expected that the leaves of the latter fruit 
would be found to be affected in a similar manner. However, 
such was not the case. No well-marked example of the trouble 
could be found on pear leaves. Sometimes the under surface of 
the leaves showed small spots gray-green in color, such as char- 
acterized the blisters on apple, but there were no wrinkles, and 
so far as could be determined from free-hand sections the epi- 
dermis was not loosened. Neither were there any dead spots 
which could be attributed to frost. 
Foliage other than that of apple, quince and pear was not 
carefully examined. Horse-chestnut leaves were very ragged 
as a result of the frost, but the injury was quite different from 
that on apple and quince. Sorauer observed the frost blisters 
on cherry leaves. The writers have observed occasional cherry 
trees on which the foliage had evidently suffered somewhat 
from frost, but there was no pronounced wrinkling of the-leaves 
and no blisters were seen. 
II. SPOTTING AND DROPPING OF APPLE LEAVES 
CAUSED BY SPRAYING. 
Early in July of the past season apple growers in westeri 
New York became considerably alarmed at an extensive spot- 
ting, yellowing and premature dropping of apple leaves. The 
serious condition of affairs was first brought to the attention of 
the Experiment Station by Mr. W. P. Rogers, of Williamson. 
Subsequently, several letters of inquiry concerning the trouble 
were received from apple growers in the counties bordering oi 
Lake Ontario. The general tone of these letters is fairly repre- 
