APPLE DISEASES 



83 



the fruiting structures of the pathogene. By late summer 

 or fall the canker may have attained a depth of one-half an 

 inch, a length of 

 ten inches, and a 

 breadth of three to 

 four inches. Some- 

 times two or more 

 cankers become 

 confluent and thus 

 larger lesions are 

 produced. In older 

 cankers, the bark 

 may drop out leav- 

 ing a wound, al- 

 though this may 

 not take place be- 

 fore the canker is 

 three years old. 

 The smaller cankers 

 sometimes heal 

 slowly by callus- 

 formation. In 

 other cases the 

 wound never heals, 

 but instead the 

 limb is completely 

 girdled. 



The disease is 

 not uncommon on 

 the fruit, either in 

 the orchard or in 

 storage. The le- 

 sions may begin anywhere on the surface; frequently they 

 center about one end, or about an injury of some sort. The 



FIG. 23. Northwestern anthracnose-cankers on 

 apple-limbs. 



