329 



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

 vaded, and tlie camlnnni is attacl^ed only rarely. In such cases where 

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

 it is less sui»erficial. 



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

 Whetzel.) 



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

 purple margins. Later the spots beconie brown, and if infection is bad 

 they may coalesce, forming large brown patches which involve a larger 

 portion of the leaf. 



Black rot (Fig. 3) begins ;'.s small darkened area. After a few days 

 alternating bands of lighter and darker colored brown appear, forming 



