LARCH DISEASES 215 



leafless stems growing out from the bark is all that can be seen. 

 A general discussion of mistletoe diseases will be found on page 

 54. 



Rbperbncbs 



Weir, J. R. Larch mistletoe : some economic considerations of its 

 injurious effects. U. S. Dept. Agr. Bui. 317 : 1-25, flgs. 1-13. 

 1916. 



Weir, J. R. Mistletoe injury to conifers in the northwest. U. S. Dept. 

 Agr. Bui. 360 : 1-38, pis. 1-4, figs. 1-27. 1916. 



Pecky Wood-Rot 



Caused by Trametes pint Fries 



Red-rot, ring-shake, peckiness or pecky wood-rot is the 

 most destructive wood-rot of conifers in the United States. 

 It is common in larch. The characteristics of the rot in larch 

 are similar to those produced in spruce, with the exception that 

 the action in the formation of pockets is less localized. The 

 spring-wood of the affected annual rings is largely destroyed, 

 leaving the denser summer-wood partially decayed and red 

 in color. Black lines are formed at irregular places. The 

 wood of the larch is thus more completely destroyed than that 

 of the other conifers. The sapwood and bark are readily in- 

 vaded and the living tissues killed, thus causing the death of 

 the parts of the tree above, as in the spruce and fir. A 

 more complete description of this wood-rot is given under 

 spruce diseases, page 324. 



Red-Brown Sapwood-Rot 



Caused by Fames pinicola Fries 



Larch wherever it grows is commonly affected by this wood- 

 rot. Spruce, pine, fir and hemlock are also affected. The 

 wood is reduced to a red-brown powdery mass held together 

 by numerous plates of whitish mycelium. The sporophores 



