THE PLUM ] 355 



of Exoascus (E. pruni Fckl.) is common all over the 

 continent and in rainy springs provokes the well known 

 diseased condition of the fruits called "bozzacchioni" by 

 Italian writers. The diseased green fruits become much 

 swollen and irregular, with an internal cavity, and soon 

 become grey or brown and rot off. These fruits are cut 

 off along with the twigs on which they grow and burned 

 to prevent the spread of the fungus ior the following year. 

 This diseased condition of the fruit of the plum has been 

 referred to by Dante in the following lines, Purg. 



Ben fiorisce negli uomini il volere 

 Ma la piog-gia continua converte 

 In bozzacchioni le susine vere. 



To Exoascus Insititiae Sad. is ascribed the formation 

 of witches' brooms on the wild plum or bullace in Italy 

 and Germany. 



Other species of fungi attack the foliage of the plum 

 in continental Europe. Sphaerelia Bellona Sacc. produces 

 whitish spots surrounded by a brown margin, and soon 

 causes the leaf to drop off. Grayish spots with minute 

 black dots are produced on the upper surface of the leaf 

 by Ascochyta chlorospora Speg. Small round or nearly 

 round spots of a brown colour with a darker margin are 

 caused by Phyllosticta prunicola Sacc. and Hendersonia , 

 foliorum Fckl. Round blistered blotches of a dark 

 brown colour are caused by Didymaria prunicola Cav., 

 and Cor yneum Beyer inckiiQ\ii&. produces reddish blotches 

 on the upper surface of the leaf. Cladosporium condy- 

 lonema Pass, produces brown irregular spots, which 

 become wrinkled, and show minute olive-green pustules, 

 Clasterosporium Amygdalearum Sacc. produces roundish ' 

 yellow blotches which afterwards turn brown, and are 

 surrounded by a dark red margin ; and Poly stigma 

 rubrum D.C. produces large, thick, roundish blotches of 

 a reddish yellow colour. Dermatella Prunastri Pers. 

 attacks the bark of the branches and twigs, causing it to 



