JUNIPER DISEASES 



197 



Fig. 31. — Cedar-appUs, early- 

 stages of development. 



Cedae-Apples 



Caused by Gymnosporangium juniperi-virginiance Schw. and 

 G. glbbosum Farlow 



The two diseases of the red 



juniper known as cedar-apples or 



cedar-flowers are similar in nature 



and are found commonly in ea,stern 



and central United States. The 



first pathogene mentioned above 



has its alternate stage on the culti- 

 vated apple and. other species of 



Malus, while the latter pathogene 



occurs on various species of haw, 



mountain ash and the cultivated 



apple, and pear. The junipers 



are often covered with hundreds of the brown, globose galls 



which spoil the appearance of 

 ornamental trees and result in 

 more or less damage to the twigs 

 and general vigor of the tree. The 

 two pathogenes are the cause of ap- 

 ple and pear rust respectively and 

 cause serious losses in yield when 

 they cause defoliation. Climatic 

 conditions and the proximity and 

 abundance of the two kinds of hosts 

 in the same locality are the deter- 

 mining factors which influence the 

 severity of these diseases on both 

 hosts. 



Symptoms. 



Brown-colored bodies called 



Fig. 32. — Cedar-apple in late in 



autumn, one year after infection, cedar-apples or cedar-flowers are 



