.57 
Brooks obtained pure cultures of tbe fungus, and carried out 
inoculation experiments on the roots of healthy trees. These were 
entirely unsuccessful and suggest that some condition adverse to 
Hevea must exist before the fungus can enter living roots. This 
condition may well be bad soil ventilation. Infection may be either 
by spore infection on wounds (on exposed roots) or contact with 
diseased jungle roots and precautions must be taken accordingly. 
Ustulma zonata . 
A disease first detected in Malaya in 1914 by Brooks — followed 
by Shamles — the latte’r author attaches more importance to the 
manife r ations of the fungus as a collar-rot than as a root disease ; 
but root attacks and spread by contact should not be neglected. 
Fetch attributes the prevalence of the disease in Ceylon on tea 
to lateral root contact from stumps of Orevillea which had been 
left in tbe ground. The characteristics of an Ustulina attack are 
— a dry rot of the attacked wood, and the production of coarse 
interlacing black lines in the wood. There is no external mycelium 
and the wood must be cut into before the disease can be found. The 
fructifications are of somewhat varied form — the most common being 
a plate-like mass, adpressed to the collar of the tree — the colour of 
which changes from yellowish- white, through grey — white and 
greenish-grey to black. In the later stages, when splashed by mud, 
tbe fruits easily escape observation.' More rarely other forms of 
fruit body are found, e.g., a solitary stalked form ; stalked forms 
aggregated to a plate ; and other lichen-like forms. All, except the 
last, produce spores in abundance, which falling or being carried to 
wounds or cuts propagate tbe fungus. It follows that the fruit 
bodies of this fungus, like those of Sphserostilbe, should be destroyed 
as soon as found. 
Brown Boot Disease ( Hymmochsete noxia). 
So far this disease has not been recorded to any great extent in 
Malaya although Petch states that it is the commonest root disease 
of Hevea in Ceylon. Characteristic of this fungus is the production 
of hard, brittle, brown or black incrustation around infected roots — 
composed of soil bound to the roots by the fungus mycelium. 
Within tbe decayed roots are often found brown lines or plates of 
fungus tissue. Diseased wood, at any rate in Malaya, remains hard, 
but may become honeycombed. Fructifications are of very rare 
occurrence and are of no practical importance. 
So far as I know, no artificial inoculations have been attempted 
with the fungus, but the disease can often be traced to a jungle 
stump. Brown root disease has usually been considered as not 
dangerous owing to its slow spread— the idea being that the attacked 
tree dies, and is taken out before tlie roots of tbe surrounding trees 
can be infected. This may he so, but it is better to be on the safe 
side, and to treat the disease like all other contact root diseases. 
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