31 



ease is very rapid, especially when the tree is subjected to 

 drouth conditions. Several conditions may occur simultaneously 

 or be manifested differently in different trees. A tree which 

 looks in fine condition except for the slightly sick appearance 

 will suddenly turn yellow and all but the tip leaves of the 

 branches fall off. Within two weeks it will be dead or nearly so 

 and loose bark or dead tissue may be found at the base of the 

 tree where the roots have died. In other trees the leaves are 

 small and not very numerous and loose bark may be found at 

 the base. These trees are the more resistant ones which dropped 

 their leaves the year before and attempted to survive the 

 following spring. In all cases where trees were dying or had 

 died, the twig growth for the last three to five years was steadily 

 shorter, showing a decline of the trees. There are several identi- 

 fying marks about Xylaria. In advanced stages when there is 

 no help for the tree, loose bark about the base over the dead 

 tissues can be found, and if this bark is peeled off it will be 

 noted that the diseased tissue extends up the trunk of the tree 

 twenty or thirty feet and finally dwindles to nothing. Even- 

 tually Xylaria can be cultured from the furthest tips of the 

 limbs, having permeated the w^hole tree. After a tree has been 

 dead for some time, or w^hen it is dying, white hyphae may be 

 seen under the loose bark, the diseased wood is punky, and, if 

 a piece of wood is chiselled out, it wall be found to contain an 

 irregular fine black line at distances ranging from the surface. 

 In most cases this is very easily demonstrated if the fungus is 

 present. On dead roots, occasionally, small upright horns about 

 an eighth of an inch high may be found. These are the fruiting 

 bodies. 



Where isolated trees become sick and die from Xylaria it 

 seems probable that the fungus spores have been distributed 

 by the wind and have entered the soil. Where elms have been 

 planted in rows, the fungus travels from root to root and from 

 tree to tree. Invariably the tree that is sickened has diseased 

 roots on the side facing the dead tree. In this way rows of 

 25 or 30 elms have become infected. 



Coniothyrium and Vermicularia are present in Danville in 

 some abundance but can be controlled and are not alarming. 

 Coniothyrium is a limb disease which enters twigs and kills 

 the cambium causing individual limbs to wilt and die. In these 



