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FUNDAMENTALS OF AGRICULTURE. 



APPLE SCAB. 



SECTION XXXVII. FRUIT CROP DISEASES. 



Apple Scab. 

 The fungus that 

 causes scab grows 

 in the skin of the 

 apple, causing the 

 waxy portion to 

 scurf off, and giv- 

 ing rise finally to 

 circular spots a 

 quarter of an 

 inch or more in 

 diameter. These 

 spots have rough, 

 brown centers, 

 and are sur- 

 rounded by a 

 margin which is 

 olive green, in 

 color, and consists of the growing fungus threads and 

 the spores. This fungus does not rot the fruit, but it 

 furnishes ready gate- 

 ways for the en- 

 trance of other fungi 

 which do cause rot; 

 for this reason 

 scabby fruit is poor 

 in keeping quality. 

 The scab fungus also 

 grows, but less con- 

 spicuously, on the 

 leaves and twigs of 

 an infected tree; and 

 in these, especially 

 on fallen leaves on 

 the ground, it re- 

 mains alive over 



winter Spores are BITTER ROT OF APPLE , CAUSED BY A 

 carried to the young FUNGUS. 



