ACCIDENTS AND DISEASES 201 



the " witch's broom," a gall growth named 

 Eriophyes triradiatus^ which produces moss-like 

 growths and injures the affected shoots. It 

 is described in the chapter on insect attacks. 



Yew. This tree is rarely uprooted by the 

 wind, though during a snowstorm the flat, 

 thickly-leaved branches are apt to get bent 

 down and broken. Being a long-lived tree, 

 hollows in the trunks and heavy branches that 

 are likely to get riven from the main stem 

 should receive attention in the matter of rilling 

 and bracing. The yew is little subject to 

 insect attacks, but is occasionally, where disease 

 has set in, the host of that widely dispersed 

 fungus Polyporus sulphureus. This should be 

 removed and, after the wound has been thor- 

 oughly cleaned of all dead and dying matter, 

 it should be painted with tar or carbolineum. 



When only a few trees are attacked by 

 insect or fungoid pests, remedies may usually 

 be applied, and often with success ; but in the 

 case of a whole plantation this is quite out of 

 the question. Prevention is best, and in con- 

 nection with this the following rules should 

 be observed : 



