THE NEW YORK APPLE.TREE CANKER.* 
(SECOND REPORT.) 
WENDELL PADDOCK. 
SUMMARY. 
Attention is called to the fact that the canker fungus, 
Spheropsis malorum Pk., occurs on several hosts; viz.: Apple, 
pear and quince fruits, and apple trees, pear trees and hawthorn 
trees. It is probable that species of Sphwropsis occurring on a 
number of other hosts are identical with this, but moculation 
experiments have not yet been carried far enough to show that 
this is so. . s 
Sun scald and sun burn undoubtedly have much to do with 
the susceptibility of some varieties of apple trees to canker. 
Spraying the trees in winter with a whitewash protects them 
to some extent from the heat of the sun’s rays, and is a partial 
preventive of sun scald. 
Training the trees. to thick, low heads, which afford shade for 
trunks and branches in summer is a partial preventive of sunburn. 
Spraying with Bordeaux mixture is recommended as a partial 
preventive of canker. , 
Nectria ditissima, a serious canker fungus of European orchards, 
-has been found on apple trees in New York and in Nova Scotia. 
INTRODUCTION. 
Previous to the publication of Bulletin 163 of this Station the 
New York apple-tree canker was scarcely known. The injuries 
had attracted the attention only of the more observing and were 
*Neprint of Bulletin No. 185, 
