APPLE DISEASES 



17 



epidermis exposing pink masses at their tips (Fig. 5). As the 

 spot increases in diameter the pustules follow rather closely the 

 advancing circumference of the lesion. At the same time the 

 spot is developing outwardly, it is also progressing inwardly, 

 and a section made perpendicular to the surface, through the 

 center of the spot, shows the rotted area to be funnel-shaped. 

 Finally, the whole 

 fruit is involved and 

 a mummy is the re- 

 sult (Fig. 5). Some 

 of the affected fruits 

 fall while others cling 

 to the tree for at 

 least a year. Spots 

 which have been re- 

 tarded by cool 

 weather have an 

 especially prominent 

 purplish margin. 

 Many late infections 

 are reddish or pur- 

 plish specks, never 

 developing further 

 on account of ad- 

 verse conditions. 



Cankers are devel- 

 oped on the twigs, limbs (Fig. 6) and fruit-spurs. Trunks 

 rarely show bitter-rot cankers. Smaller twigs are some- 

 times wholly and suddenly killed, resulting in a twig-blight. 

 The Jonathan and Willow varieties are more subject to this 

 type of injury than others. Most cankers on the limbs have 

 at their center a dead twig or evidence of one having been 

 there (Fig. 6). The canker is at first a small discolored area in 

 the outer bark, the smooth edges of which are sharply set off, 



FIG. 6. Bitter-rot cankers. 



