82 FUNGI AXD FUNGICIDES 



pipe, by means of Tvhich the operator can spray any part 

 of the vines. The great increase in value of sprayed 

 over nnsprayed grapes has been repeatedly demonstrated. 

 It has been found that sj^rayiug with Bordeaux mixture 

 not only prevents the disease, but keeps the vines in a 

 much healthier and more thrifty condition than un- 

 sprayed vines not diseased. 



Literature. — The black rot fungus has been very 

 frequently discussed in recent horticultural literature, 

 esi^ecially by Messrs. Scribner, Galloway, Chester and 

 others. The principal articles are to be found as fol- 

 lows : United States Department of Agriculture, Re- 

 ports, 1886, pp. 109-112; 1887, pp. 326-327; 1888, pp. 

 326-334; 1889, pp, 399-405 ; 1890, pp. 394-396, and in 

 various bulletins; Delaware Experiment Station, Bul- 

 letins Nos. VI and X ; Proceedings Society Promotion 

 of Agricultural Science, 1888, pp. 68-73; 1889, pp. 

 62-64 ; 1890, pp. 58-63. 



The Downy Mildew 



Peronospora viticola 



In the Northern States the downy mildew, or 

 brown rot, is one of the most destructive fungus ene- 

 mies of the grape. It is distributed over nearly the 

 entire eastern half of the United States, and occurs both 

 upon the wild and cultivated varieties of grapes. It 

 probably lived upon the former before the introduction 

 of the latter. It appears usually about the time the 

 vines blossom, producing upon the leaves a distinct 

 whitish mildew which has earned for it its common 

 name. The leaves, and often the young shoots, are 

 more or less injured, and from them the fungus spreads 

 to the newly formed berries, coating them also with mil- 

 dew and causing them to fall off. The damage contin- 

 ues throughout the summer. When larger grape berries 



