54 Diseases. 



BUSHBERG CATALOGUE. 



Galloway. 



country east of the Rock}' Mountains. So 

 far as we are aware it has not reached Cali- 

 fornia, but it is probably only a question of 

 time when it will appear there. While black 

 rot is present everywhere east of the Missis- 

 sippi River, it is in and south of the States of 

 New Jersey, Virginia, Ohio, Indiana, Illinois, 

 and Missouri that it has proved most virulent, 

 frequently' destroying from 50 to 100 per cent 

 of the crop. In 1885 the disease appeared 

 in France, and for a time caused much alarm 

 in all the grape-growing regions of Europe. 



Black rot ma}^ be distinguished from the 

 other diseases under consideration in several 

 waj's. In the first place it must be borne in 

 mind that it is not confined to the fruit, but 

 occurs on the leaves and young branches as 

 well. The berries when first attacked show 

 at one or more points upon their surface 

 small, brownish, more or less circular discolor- 

 ations. These rapidly enlarge and soon the 

 rest of the berry turns brown, while the part 

 first attacked assumes a blackish hue. Minute 

 pimples now appear scattered irregularly' over 



Fig. 77.— Bi.ACK HOT. 



the surface, and finally the berry withers, 

 turns black, and ultimately dries up, but as 

 a rule remains firmly attached to the stalk, as 

 shown in Fig. 77. 



As a rule the leaves show the disease about 

 two days before the berries are attacked. 

 Reddish-brown, more or less circular spots 

 appear, and these soon run together, forming 

 irregular-shaped blotche.'^. ^^'hat distinguishes 

 I he spots or blotches on the leaves from sim- 

 ilar discolorations produced by certain at- 



mospheric conditions is the presence of black 

 specks, no larger than a pin point, scattered 

 over the surface or grouped in a narrow band 

 near the edge of the affected parts. The 

 specks may be seen with the naked eye, but 

 with a low-power magnifying glass they are 

 brought out more prominently. 



Doirny mikleir.* — The diseases known in 

 various sections as American mildew, brown 

 rot, gray rot, grape Peronospora, etc , are all 

 due to one and the same fungus, viz, 7'ero/(OS- 

 2)ora viticola. The dowu}^ mildew fungus has 

 a wider distribution than black rot, and prob- 

 ably in the aggregate causes more damage. 

 It occurs in nearly all the grape-growing 

 regions of this country, and is also common 

 in Europe and other parts of the Eastern 

 Hemisi^here. 



Leaves affected with downy mildew show 

 upon the upper surface greeuish-3'ellow or 

 brownish spots, of irregular size and shape, 

 while opposite these discolorations, on the 

 lower side, a downy, whitish, frost-like 

 growth may be seen. In advanced stages of 



lijr. Ts.— Hhowx rot. 



the disease or after a heavy rain the frost-like 

 patches often disappear, leaving in their 

 places light brown discolorations correspond- 

 ing in size and shape with those on the upper 

 side. 



The fruit is frequently Attacked, especially 

 when 3'oung, the berries being covered with 

 the downy, whitish growth of the fungus, sim- 

 ilar to that occurring on the leaves. It is 

 very common also in many sections to find 



* Peronospora viticola B. & C 



