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MANVAL OF TREE DISEASES 



butternut, walnut, hickory and oak. Its range of hosts is 

 larger than any other wood-rotting fungus and its distribution 

 is limited only by the combined range of its hosts, for it is 

 found on all the continents of the world and occurs from 



Fig. 58. — Common white wood-rot in maple, with a yoimg fruiting-body of 

 the causal fungus at the right. 



tropical regions far into colder arctic zones, both to the 

 north and south. 



In Europe it is the most common disease of the oak and the 

 most dangerous wood disease of fruit-trees of the genera Pyrus 

 and Prunus. In this country beech, poplar and oak are the 

 most commonly and destructively affected. Fruit-trees, es- 



