CHAPTER XXII 

 JUNIPER DISEASES 



Seveeal species of juniper (Junipems) occur as important 

 forest-trees over the entire United States. These trees and the 

 horticultural varieties of the native and exotic species are the 

 most common conifers used for ornament. In the genus 

 Juniperus are included the low junipers. 



The juniper is subject to several important wood-rots and 

 rust-diseases. Several destructive heartwood-rots of juni- 

 per are especially common in the Southwest. The rust- 

 diseases of juniper are important both from the economic 

 and ornamental standpoint. Many of the rust-fungi be- 

 longing to the genus Gymnosporangium grow parasiti- 

 cally in the leaves, branches or trunk of juniper. Several 

 types of over-growth occm* in the affected tissues. These 

 diseases are interesting because of the complicated life history 

 of the different species requiring various other plants as altera 

 nate hosts. As certain of these fungi cause the rust-diseases of 

 apple, pear and quince, their control is an orchard as well as an 

 ornamental tree problem. 



Seedling Twig-Blight 

 Caused by Phoma sp. 



Junipers grown in nursery-beds are subject to a twig-blight 

 which has been destructive in certain seasons in Kansas, Ne- 

 braska, Iowa, Illinois and Pennsylvania and may be expected 

 in other localities. By artificial inoculation with the causal 



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