Pomaceous Fruits 



45 



disease in 1902 l)y Hasselbring, who attributed to it more 

 serious results than from any other canker disease of IlUnois. 

 In many cases largo lim])s and even whole trees are killed. It 

 has been reported in many states, including Arkansas, Okla- 

 homa, Nebraska, New Hampshire, New York, and Virginia. 



The cankers arc at first in- 

 conspicuous, unhealthy, dirty 

 brown, usually depressed 

 spots in the bark, sometimes 

 15 cm. in diameter, which 

 enlarge rapidly, particularly 

 lengthwise upon the limb, a 

 crack often marking the 

 boundary between dead and 

 sound bark. The interior of 

 the bark of such spots is 

 mottled with dead regions. 



In autumn the sporiferous 

 bodies appear near the bor- 

 ders of the diseased spots, first 

 pushing through cracks in 

 the bark, and exposing pale 

 grayish ochre-colored fungous 

 growths 3-6 mm. in diani- 

 eter,which, when mature, are 

 slightly saucer-shaped, and 

 dark in color. These bodies 

 are attached to the dead 

 wood, and remain there even 

 after the bark has fallen 

 away, thus constituting a 



diagnostic character of absolute reliability, separating this 

 from all other cankers. Discoloration of the heartwood 

 often occurs at a distance of a meter or more from the ap- 

 parent seat of disease. 



When the cankers become large, injury to the distal parts 

 through interruption of the water supply results. The 



Fig, 



19. — Black-spot on fruit. 

 After Lawrence. 



