329 



in the figure. The writer has not seen cases where healthy wood is in- 

 vaded, and the canil)iuni is attacked only rarely. In such cases where 

 only the barlv layer is attacked, the canker is not so destructive as when 

 it is less superficial. 



Fig. 3. Black rot oi apple. Enlarged to show distribation of Iruit bodies of the fungus. (After 

 Whetzel.) 



"Frog-eye" spots on leaves begin as small reddish lirown spots with 

 imrple margins. Later the spots become brown, and if infection is bad 

 tliey may coalesce, forming large br^wn patches which involve a larger 

 portion of the leaf. 



Black rot (Fig. 3) begins as small darkened area. After a few days 

 alternating bands of lighter and darker colored brown appear, forming 



