DISEASES OF THE VINK. ] 579 



VEGETABLE PARASITES. 



Tubercle of the Vine. ( 1 1. = Ro$nfi delta vite) . This 

 disease consists of warty and corky growths on the stem 

 and branches, particularly on the growing callus of 

 won ids caused by pruning or by any other lesion of the 

 woo ly tissues. The development of the tubercle is due 

 to the presence of Bacillus ampefopsoroe Trev., just as 

 the tubercle of the olive-tree is due to Bacillus oleae. 

 This disease is fortunately rare in our vineyards, and 

 American vines are said to be generally free from this 

 infection, against which it has been recommeded to cut 

 off the warty growths and burn them, washing the wound 

 with a strong solution of green vitriol (ferrous sulphate). 

 In cases of severe infection it is better to remove the 

 plant altogether, and burn it. 



Black Disease. (\t. malnero). Is a gurnnosis of 

 the vine, and is due to the presence of a microbe, Bacillus 

 vitivovus Baccarini. This disease attacks all parts of 

 the plant, including the stem and the berries, and makes 

 its appearance towards the close of May or early in 

 June ; the shoots cease to grow, and become limp 

 at t'ie extremity ; the leaves wither, become crumpled 

 and dry, assuming a yellow, reddish brown or purp- 

 lish brown colour. The shoots show -a livid appearance 

 at the node, where they break off easily, dark chocolate 

 brown streaks are formed along the internodes, and the 

 pith becomes soft and rotten, and takes a coffee brown 

 colour. The bunches become atrophied, and few berries 

 are retained. On the stem the disease develops long 

 deep fissures, having a cankerous aspect, from which 

 a dark, thick, sticky fluid oozes out, which is full of 

 the microbe abovementioned. The disease is favoured 

 by bad drainage, and by the habit of deep planting, 

 the infection often starting at the heel of a long 

 cutting which has been inserted deep into the soil. 

 When the disease starts from a wound above the surface 



