91 



Coincident with the above experiments, others were in progress 

 where sterilized media were inoculated with the bark of healthy 

 rubber trees (sent from Sungei Tengah Estate), and whilst in some 

 cases no fungoid growths appeared within 48 hours, in no case was 

 the vitality so pronounced, nor did the same organisms predominate. 



Besides the sporiferous bacillus mentioned above, a white thread- 

 like fungus was separated, which bore a strong resemblance to a 

 fungus [H elicobasidiuni) which has been described as attacking the 

 roots of rubber trees and spreading from tree to tree by strands of 

 mycelium in the soil. 



The life history of this organism was followed as far as possible, 

 and the results fully justified the apprehensions of its capabilities. 



I regret that through lack of the necessary literature, I am unable 

 to complete the identification of the fungi. 



That so many trees should have showed signs of disease at one 

 time, seems to point to trouble in the nursery rather than on the 

 Estate, for disease, however rapidly spread, takes time. One 

 diseased sapling in the nursery is more than capable of furnishing 

 sufficient germs to inoculate all others. 



When a germ finds conditions unsuited for its growth, it very 

 frequently forms spores which are probably the most retentive form 

 of life known. On the return of favourable conditions the spore 

 germinates into the vegetative form which again multiplies. 



The advantages of a marked dry and wet season are here very 

 apparent. During the dry season the fungi are likely to revert to 

 spores and become inactive. When the wet season comes the fungi 

 again become active, but during the interval the tree has regained 

 any lost vitality, and so is better fitted to withstand further attacks. 



In the absence of a comparatively dry spell the tree would 

 obviously be deprived of this period of recuperation. 



To sum up, the site of the nursery might be changed with 

 advantage. The affected area ought certainly to be trenched, and 

 means taken to prevent, if possible, further propagation of the 

 disease which at this season of the year is much more likely to 

 spread by the agency of the soil, than by that of the wind. 



In making new nurseries there seems no reason why the seeds 

 should not be planted at greater intervals apart than has hitherto 

 been the practice. The Puak soil is undoubtedly a poor one, and it 

 stands to reason that, if you wish to produce strong healthy plants, 

 capable of resisting the attacks of this disease, you must give them 

 more room and air to compensate for the poverty of the soil. 



I should also judge that the vitality of a plant at the end of a 

 prolonged spell of either wet or dry weather is at a low ebb, and, 

 although if planted out on an estate where the soil is rich, it would 

 probably grow, still if it is in a diseased condition on leaving the 

 nursery and is planted in a soil capable of affording it but little 

 nourishment, the combination of these adverse factors is probably 

 more than the tree can contend with. 



