PLANT DISEASES 



439 



Another kind of mildew (" powdery mildew ") attacks the 

 young grapes, producing corky spots that destroy the value 



FIG. 88. Grape leaf, showing patches of downy mildew. 



of the fruit. This spotting of the fruit does not destroy the 

 plant, for it is only a skin disease, but it destroys the value 

 of the plant for our use. 



