212 Some Diseases of Plantation Rubber in Malaya 



so spent is in the nature of insurance for the future. The welfare of 

 the plantation rubber industry is dependent upon many factors, but 

 it is obvious that without health in the trees this flourishing industry 

 would cease to exist. 



2. Fames Ugnosus, Klotzsch. 



This fungus which is the commonest cause of root disease of Hevea 

 in Malaya is better known under the name, Fomes semitostus. Petch (li), 

 however, has pointed out that Fomes semitostus proper is an entirely 

 different fungus and that the correct designation of the fungus causing 

 root disease of Hevea is Fomes Ugnosus, Klotzsch. 



Soon after the establishment of rubber estates upon an extensive 

 scale in Malaya this fungus became particularly troublesome in young 

 plantations. As is well known it begins to grow upon the stumps 

 which remain after the operations involved in planting up jungle land, 

 and spreads thence by means of thick, yellowish white, mycelial strands 

 which travel underground to the roots of young rubber trees. When 

 the mycelium reaches the collar of the tree and spreads around it the 

 tree dies. 



Until recently the only mode of treatment for this disease used on 

 a large scale lay in the destruction of affected trees and the isolation 

 of diseased areas by means of trenches, but according to Richards (12) 

 and Colenbrander(9) considerable success has been obtained by treating 

 the roots of trees in the early stages of attack in the following manner. 

 All trees are examined by opening the soil around the collar and if 

 traces of mycelium are found the roots are fully exposed. Dead portions 

 of roots are cut off, the external mycelium around living parts is scraped 

 away, and the surfaces are then covered with a thin Bordeaux paste. 

 The surrounding area is dug, all mycelial strands and dead wood being 

 burnt. Richards (12) states that 75 per cent, of the trees affected on 

 some estates have been successfully treated in this manner. A method 

 similar to the above, but in which carbolineum is used instead of 

 Bordeaux mixture, is described by Rutgers and Arens(16) as being 

 used in Sumatra by His. 



Since Fomes Ugnosus has been recognised to he a serious rod parasite 

 it has become customary on some estates to clear the land of jungle 

 stumps and other timber a leu years after planting. The cost of clearing 

 varies greatly indifferent districts and depends largely upon the relative 



heaviness of the jungle that formerly covered the ground. Some of 



