268 



SEVENTEENTH AND EIGHTEENTH 



elled and distorted, eventually dropping off. The fungus 

 also attacks the stems of apples, sometimes causing the young 



Fig. 11. Apples affected with scab fungus (photo by Lamson). 



fruit to shrivel and fall. But the most serious effects of 

 this parasite are found on the fruit. Here the fungus pro- 

 duces olive-black spots, which in their late stages have a 

 narrow margin of light gray. When the scab spots are 

 abundant the fruit is often dwarfed, cracked and deformed ; 



