THE GRAPE. 165 



mentioned as a remedy, but only as indicating 

 the sensitiveness of the microscopic plant. As 

 has been said, there are several forms of mil- 

 dew which attack the grape, and it is neces- 

 sary to give heed to this in applying remedies. 



The Powdery Mildew (^Unoinula ampelopsi- 

 dis), which is of the same species as the vari- 

 eties found upon the gooseberry, the rose, the 

 pea, and the lilac, shows itself early in the sea- 

 son as delicate, dust-like patches on the leaves 

 of the grape, mostly on the upper surface, and 

 to some extent on the fruit and tender shoots. 

 It is widely distributed, but is less destructive 

 than other forms, and as it is easily destroyed, 

 the evil is not serious. All of the powdery 

 varieties grow entirely upon the surface of the 

 plants which they infest, and hence yield at 

 once to treatment. Simply dusting the vines 

 with flowers of sulphur three times; once when 

 the shoots are four inches long ; again when 

 the vines are in bloom, and again before the 

 coloring of the fruit, is sufficient in most in- 

 stances. In grape-houses the fumes of sulphur 

 melted in a basin over a lamp are effectual. 

 But great care must be taken to prevent burn- 

 ing of the sulphur, the gas of which is fatal to 

 all vegetation. 



Downy Mildew (Peronospora viticola). — This 

 is also known as Brown Rot, and is a more 



