CHAPTER XXIX 

 SPRUCE DISEASES 



Six or more species of spruce (Picea) grow as forest-trees in 

 the United States. They are important timber-trees and occur 

 most abundantly in the northern states, although their range 

 extends southward in the mountains to North Carolina, Ten- 

 nessee, Colorado and California. Spruce is also extensively 

 used as an ornamental. 



Several diseases cause damage to spruce in the forest. The 

 most important disease affecting these trees is the pecky wood- 

 rot. Red-brown sapwood-rot and other diseases of the wood 

 are also important. Several rust-fungi attack the leaves, 

 twigs and cones of spruce. Two of the rusts cause witches'- 

 brooms. Other minor diseases cause more or less loss in different 

 sections of the country. As an ornamental, spruce is usually a 

 healthy tree. 



Seedling Twig-Blight 



Caused by Ascochyta piniperda Lindau 



This blight has been a common source of loss in seed-beds in 

 Europe for many years but has only recently been reported in 

 this country. It is known to occur in North Carolina on white 

 and red spruce seedlings. More or less severe damage to 

 seedlings of Norway and Sitka spruce are reported from Ger- 

 many, Russia and Austria. It is also proved that a disease 

 of the twigs of older spruce trees in the forest in Europe is 

 caused by the same fungus. On both seedlings and older trees, 

 this disease is sometimes confused with frost-injury which it 



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