170 DISEASES OF ECONOMIC PLANTS 



Bird's eye, anthracnose (Sphaceloma ampelinum DeBy.). 

 — This anthracnose, probably introduced into America from 

 Europe prior to 1880, is now widely distributed throughout 

 grape-growing sections. While not usually so destructive 

 as the black rot or the brown rot, it sometimes increases to 

 such an extent as to do great damage, even causing in some 

 instances the loss of all the berries upon a vine as well as 

 much injury to the canes. During damp, warm weather it 

 develops rapidly, affecting some varieties more than others. 

 The Brighton and Moore's Diamond may be mentioned as 

 especially susceptible. 



Upon the canes the anthracnose is first seen as small, dark 

 brown or black spots, which soon become sunl<:en in the 

 centers. The spots usually enlarge most rapidly in the 

 direction lengthwise of the stem, though they may sometimes 

 girdle it. Girdling is particularly common upon stem 

 clusters, where it is always fatal. The centers of the older 

 spots are ashen in color, the edges dark, and the cankerlike 

 spot extends from the bark deep into the wood, rendering 

 the shoot weak and brittle. 



Upon the fruit spots 3-5 mm. in diameter are produced 

 similar to those upon the canes, except that the center does 

 not always become ashen. Here, too, a band of red often 

 surrounds the diseased part. The parts of the berry adja- 

 cent to the diseased spot remain green and develop normally, 

 which, associated with the red border, results in the peculiar 

 appearance which has led this disease to bear the name 

 '' bird's-eye disease." 



If the berry is attacked while young, it may either 

 outgrow the disease or succumb to it. Several spots 

 upon one berry destroy its value, and spots upon one 



