'( 5 ) 
is most common in the coastal areas. Occasionally 
this fungus destroys large areas of rubber but 
usually its action is slow and only individual trees 
are attacked. 
The more characteristic features are the fiat, 
black, interweaving rhizomorphic strands, seen 
closely adpressed to the wood when the bark is 
removed from the diseased roots, and the fruits of 
the fungus which, when present, are typical though 
rather minute. The soil round the roots of an 
attacked tree and the diseased wood as a rule give 
off a most unpleasant odour when freshly dug up. 
Ustulina zonata. 
This fungus disease is wide-spread, and numer- 
ous cases can be found in many old plantations. 
The fungus is capable of attacking any part of the 
tree, i.e. root, stem or branch, if the wood is exposed. 
It often works in conjunction with boring beetles; 
the insects, after penetrating the wood, are followed 
by the fungus, and, in such cases, the trees are 
killed very rapidly. The fungus often enters the 
stem at places where large branches are broken off 
by the wind or other agencies. 
In all cases in which Ustulina zonata is active 
in tissues of Hevea brasiliensis, the appearance is 
the same, — a typical dry rot of the woody tissues 
with numerous conspicuous black lines, running 
through the rotted wood. The disease is most com- 
mon on trees over eight years of age. 
Fomes pseudo-ferreus (Wet-Root Rot). 
The action of this fungus on roots of Hevea 
brasiliensis is very distinct from that of Ustulina 
zonata . Fomes pseudo-ferreus produces a typical* 
“ wet-rot," in whatever situation the attacked tree 
