124 MANUAL OF TREE DISEASES 



fruiting-structures on the under sides of the dead areas. Spores 

 from these structures are produced in abundance during wet 

 weather and are disseminated by rain. After the leaves fall, 

 perithecia are formed and from these ascospores are available 

 in the spring for primary infection. The name applied to the 

 perithecial stage is Gnomonia leptostyla (Fries) Ces. and De 

 Not. For a further discussion of leaf-spots and their control, 

 see page 27. 



Common White Wood-Rot 



Caused by Fames igniarius Fries 



The butternut is sometimes affected by the common white 

 wood-rot, which occurs in many kinds of deciduous trees, 

 especially poplar, beech, oak and maple. The sporophores 

 of the fungus and the characteristics of the rot are similar for 

 all the kinds of trees affected and are described under poplar 

 diseases, page 305. 



Brown Checked Wood-Rot 



Caused by Polyporus sidphureus Fnes 



Butternut is occasionally affected by the brown checked 

 wood-rot, caused by the sulfur fungus. Many other kinds 

 of trees are affected by the same disease. The sulfur-yellow, 

 annual fruiting-bodies of the fungus togethpr with the brown 

 powdery character of the rotted wood make it easy to identify 

 this disease. The tops of trees and large limbs may be killed 

 by the invasion of the sapwood and bark. A more complete 

 discussion of this wood-rot will be found under oak diseases, 

 page 247. 



