290 



interesting to note that in ground where there are other trees than 

 Para rubber it does not seem to destroy these. Thus in the infected 

 ground are young trees of Cananga, and Afzelia which are quite 

 unaffected by it. 



In the garden jungle, some time ago, I found the dying stump of 

 some tree bearing a large fructification of Fomes in actual contact 

 with a gutta percha tree, but this latter was not injured by the fungus, 

 nor do I see any other trees near the old stumps affected at all. 

 Fomes, as a parasite, is not by any means confined to Para 

 rubber, and I have seen it attacking other living trees, in forest, but 

 in the case of mixed trees it does not seem to spread in the steady 

 way it does in a plantation of Hevea. 



This suggests that when the mycelium of a saprophytic fungus 

 takes on a parasitic nature and as a parasite attacks any particular 

 kind of tree, its attacks are confined to that species. 



It is certainly rare to find a fungus destroying all the trees and 

 shrubs around its centre of infection in a mixed forest. But more 

 observations and experiments are wanted on this subject. 



DIPLODIA RAPAX. 



This fungus seems to be widely spread in the peninsula and is, 

 we are informed, being kept in check, where it appears, by amputating 

 infected branches which it is found to be attacking. The fungus is 

 undoubtedly a dangerous one, as it is very quick in its life-history 

 reproducing its spores in a week after infection, and in great quantity. 

 The parasite is a wound-fungus and does not seem able to attack 

 uninjured epidermis, except in the case of young leaves as mentioned 

 below, so that thumb nail pruning, or topping, is dangerous if the 

 fungus is in the vicinity. 



The following notes in its behaviour under cultivation will be of 

 interest. 



On May lOth, we received portions of a Para rubber tree from 

 Sarawak, which had been killed by disease. Our correspondent 

 writes "this disease has attacked our 2 year old and four months 

 trees. The first sign is a small quantity of gummy latex which 

 sticks to the trunk. All the trees seem to start the attack, above the 

 branches or high up if there are no branches. The leaves wither and 

 the tree looks as if it was attacked by Fomes semitostus, but there is 

 nothing wrong with the root. The leaves fade away rapidly. The bark 

 outside appears quite fresh and healthy but inside, on the cambium, it 

 is a pale dull red colour ; there is practically no latex in the bark. If 

 the tree is left a few days "bubok " (beetles) get in and start boring. 

 The trees seem to die in a few days when once attacked." The stem 

 sent was three inches through in the thickest parts, and was perfectly 

 dead, all the cambium being black and rotten. On the upper green 

 part of the shoot and for some way down were brown discolorations 

 covered with raised black dots from which I could not obtain any 



