THE NEW YORK APPLE TREE CANKER/ 

 (SECOND REPORT.) 



Wendell Paddock. 



SUMMARY. 



Attention is called to the fact that the canker fungus, 

 Sphwropsis 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 Sj)ficeropsis occurring on a 

 number of other hosts are identical with this, but inoculation 

 experiments have not yet been carried far enough to show that 

 this is so. 



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 tMs Station the 

 New York apple-tree canker was scarcely known. The injuries 

 had attracted the attention only of the more observing and were 



♦Eeprinl of Bulletin No. 185. 



