56 Diseases of Economic Plants 



It may easily be rubbed off with a cloth. The loss in ready 

 salability, due to the unsightliness of the fruit, is reason 

 enough for protective sprayings. Bordeaux mixture applied 

 at intervals of about two weeks from the middle of June until 

 the middle of August is effective. 



-Fly-speck. ^"- — Growing upon the surface of the fruit and 

 forming numerous clustered black specks closely resembling 



Fig. 27. — Fly- speck (at left); Sooty-blotch (at right). After Colby. 



fly-specks, this fungus causes disfigurement of the apple. 

 The generic position of the fungus is in doubt, though it 

 was originally named Lahrella pomi by Montague. 



Volutella rot*^^ (Volutella fructi S. & H.). — In general 

 appearance the volutella rot is not readily distinguished from 

 black-rot, though the texture of the rotted tissue is much 

 firmer and drier. Under the hand lens the sporiferous 

 pustules are seen to be clothed with numerous hairs, which 

 character sufficiently marks it as a separate disease. It has 

 been reported from North Carolina, New York, Wisconsin, 

 and is probably of general distribution. 



Scurf, an affection of the bark of twigs, is due to Phyllo- 

 stida prunicola (Opiz.) Sacc. ; Bark-canker '- due to Myxospo- 



