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. 
