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Pona hypolateritia. 
This fungus, causing a wet-rot of Hevea was the subject of an 
article in the August Agricultural Bulletin for 1916. It appears 
since, that the specific name hypolateritia there given was not correct, 
and the fungus is nearer to one recently described by Petch in Ceylon 
as Pona hypobrunnea. The matter has been referred to Kew, and 
the final name will be settled by the authorities there. Whatever 
the systematic name, there is no doubt of the presence of the fungus, 
and of its characteristics, the chief of which is the wet rotting of 
attacked roots. This may vary from a slight dampness of recently 
attacked roots only discoverable on splitting, to the complete 
disintegration of the root to a jelly-like mass. 
A very delicate snow-white mycelium is sometimes produced on 
the exterior, but no strands travelling through the soil have ever 
been found. The exterior of the root is sometimes covered by a 
very dark reddish skin of mycelium and bark tissues mixed ; this 
skin is tough, and when freshly taken up can readily be detached 
from the wood — serving to distinguish an attack of this fungus from 
that of brown root disease ; in the latter case the external crust is 
brittle and cannot be separated from the wood. 
Brown lines or plates of hardened fungus tissue are often found. 
They differ from those produced by Ustulina in colour and texture, 
being much finer and less branched. Broad brown bands also 
occur, formed by the deposition of a substance akin to wound-gum. 
Attacks of Poria sometimes cause honeycombing of Hevea wood, but 
the phenomenon is more common when hard jungle woods are 
attacked. Like Fomes the fungus has been found both on hard and 
soft woods, including mauy of the largest stumps such as are very 
often left in otherwise cleared plantations. 
Perfectly developed fructifications are very rare ; more commonly 
on the under-side of exposed roots, small patches of an imperfect 
fructification develop. The fungus belongs to the same group as 
Fames — and the fructifications have the same form as the resupinate 
form of Fomes , i.e., a plate perforated with many fine holes. The 
colour is white when young, later becoming red-brown to black. 
These fructifications are sterile, i.e., bear no spores, and cannot 
spread the disease. 
It was first thought that the disease might be confined to special 
areas, particularly flat wet lands — but it has since been found to be 
distributed through the Peninsula. 
The mode of infection is by contact of lateral roots with jungle 
stumps, or with other laterals ; and the peculiar danger of the disease 
lies in its very slow rate of growth in living tissue, which makes it 
possible for neighbouring trees to be infected — through laterals — 
before the first infected tree is seen to be diseased. This insidious 
method of attack is further aided by the partiality of the fungus to 
