46 



Letters on the Diseases of Plants. 



VIII. Diseases or the Grape. 



OiDiUM is a disease well known to attack grapes at a time when they are as 

 large as small marbles. That it may in some cases attack the fruit soon after 

 it sets is not so well known. The accompanying figure shows a bunch of some 

 grapes that set late, and so far as I could make out, were blighted at an early 

 stage by o'idium. There had been no climatic or other known hindrance to 



Fig. 56. — Bunch of grapes attacked by the disease oidium. a. Berries with skin shrivelled 

 by the disease ; b, small berries also attacked by the disease ; c, a berry still com- 

 paratively healthy. 



development, and, moreover, the smaller berries were attacked by the fungus. 

 This observation leads one to question whether we begin early enough in the 

 season to apply our flowers of sulphur, the well known remedy for this disease. 



