ARBOR-VITM DISEASES 91 



Control. 



Preliminary experiments seem to indicate that soap-bordeaux 

 mixture applied to young trees, every ten days or oftener in 

 the autumn, will greatly reduce the amount of infection. 



Repekbnces 



Weir, J. R. Keithia thujina, the cause of a serious leaf disease of the 

 western red cedar. Phytopathology 6 : 360-363, figs. 1-2. 1916. 



Durand, E. J. The genus Keithia. Mycologia 5:6-11, pi. 81. 

 1913. 



Brown Pocket Heabtwood-Rot 



Caused by Fames roseus Fries 



There are few statements in literature concerning the fungi 

 which cause the decay of the wood and roots of arbor-vitae. 

 Mention is made of brown pockets of decay in wood of the trunk 

 which are probably due to Fames roseus. This fungus causes 

 a heartwood-rot of fir, juniper, larch, spruce, pine, and hemlock. 

 The fruiting-bodies have been found also on a few deciduous 

 trees. The decay caused by this fungus is described under 

 juniper diseases (page 204). The color of the decayed wood 

 varies from dark to a lighter brown according to whether the 

 normal wood is deeply colored or not. In some cases the 

 similarity between the effects of Fomes roseiis and Polyporus 

 Schweinitsii may 'lead to confusion as to which is the true cause 

 of the rot, unless the sporophores are found attached to the 

 tree in question. 



Red-Brown Root- and Butt-Rot 



Caused by Polyporus Schweinitzii Fries 



This is one of the few wood-rots of conifers which occurs 

 in arbor-vitse. Pine, fir, spruce, hemlock and larch are seri- 



