494 



White Rot" of Vines. 



[nov m 



cocious varieties ; with shy bearers no good results are likely to 

 follow. 



With apple trees, during the first five or six years after 

 planting there appears to be a tendency for individual trees 

 to bear well or badly for several years in succession, but as the 

 tree gets older an opposite tendency manifests itself, and then, 

 as a rule, a tree which bears well or badly in one season will 

 bear in the reverse way the next season. 



The fungus called Coniothyrium diplodiella, or " White Rot " 

 of Vines, was described in this Journal in October, 1904, and 



account may be usefullysupplemented by thedrawing on the next 

 page, which illustrates the disease attacking the fruit and the stalk. 



The fruit is the part most frequently attacked, and in severe 

 cases the fungus spreads from the stalk of the bunch of fruit to 

 the branch from which it springs ; the foliage is never attacked. 

 When once established, the disease spreads rapidly, and usually 

 every grape on a bunch becomes diseased, owing to the numerous 

 minute spores of the fungus being conveyed by rain, syringing, 

 &c, from diseased to healthy berries. During the first stage 

 of disease the berries become pale brown in colour, and soon 

 commence to shrivel, but do not fall. At a later stage, when 

 the shrivelled berries have become dry, the skin assumes a dull 

 silvery appearance, and is covered with minute whitish pimples 

 representing the fruit of the fungus. 



When the stalk of a diseased bunch is attacked, the fungus 

 often extends to the supporting branch, where it forms slightly 

 depressed areas, which are at first brownish in colour, but after- 

 wards studded with the characteristic white pustules of fungus 

 fruit. The diseased patches may extend for several inches 

 down one side, or the branch may be completely girdled by 

 an irregular zone of diseased tissue, and if this is the case 

 that portion of the branch above the injured zone soon dies. 

 In vineyards the disease is most injurious during seasons of 

 great humidity accompanied by warmth. Under such conditions 



"White Rot 

 of Vines. 



it was mentioned that during recent years 

 it has frequently been met with on vines 

 growing under glass in this country. This 



