383 
to another. Seedling rubbers do not seem to be attacked by this 
fungus if left in the infected ground, but I would not advise an im- 
mediate replant. It would be better to fallow the infected ground, or 
as I have suggested to run bananas or some such plant through the 
spot to clean it up. 
Diplodia. 
I will now say a few words about the more troublesome fungus 
Diplodia. This pest has been called Dieback, but as I am by no means 
certain that all the diseases here and in Ceylon which have been called 
Dieback are the same thing for fear of mistakes I prefer to use the 
scientific name of Diplodia which, unlike many scientific names, is easy 
to pronounce and remember. This fungus is very small and incons- 
picuous. Its spores are very minute and produced in immense abun- 
dance after rain. When these spores reach a wounded rubber tree, 
they germinate in twelve hours, putting out a minute thread which 
enters the cambium layer and commences to grow. It generally, if 
not always, attacks a cut or broken shoot and descending kills the 
cambium layer. The growth is rapid and it has been known to kill a 
four year old tree in about three w r eeks after its first being noticed. All 
that is visible at first is that the top of the branch is dead ; it generally 
exudes a little latex which runs down and turning black makes fairly 
conspicuous streaks, but this is not alw r ays visible. On the bark are 
to be seen little raised pustules with a crack across the centre, these 
are black within. As soon as rain falls the fruit ripens and a substance 
like soot appears in strings and irregular masses, from these pustules. 
This substance consists of myriads of minute spores, elliptic and 
divided transversely in two and black in colour. In the case of a 
seedling the disease pushes down the stem killing it as it goes, but in 
a strong plant, its course is checked. The seedling throws out a 
beed, below the dead and dying end, the disease-stops and the dead 
portion falls off. You will see at once the danger of this pest. It 
starts almost out of sight in big trees, at the end of a shoot, it is 
difficult to get at, it is readily dispersed to great distances by the wind, 
its spores are produced in unusually large amount, and it is very 
rapid in growth and development. 
When detected it can be checked by cutting off the infected 
bough and burning it, at the same time spraying liberally with bor- 
deaux mixture. Still a tree may be badly injured and at least its 
output of latex restricted by the necessary amputation. However, in 
carefully watched plantations the injury may be minimised. But are 
all plantations carefully watched? Para rubber is planted all over 
the country by all sorts of people, little patches of half a dozen trees 
here and there, native plantations which the owner perhaps hardly 
looks at once a week, and then only cursorily. Any one will see that 
a patch of trees may r be infected, neglected, and form a focus for the 
dispersal of spores in every direction. One large-sized badly infected 
tree could produce enough spores to thoroughly infect a large area. 
It is to this danger that I would calf your attention. Rapid as is th$ 
