59^ RUBBER 



disease was tried at Peradeniya about four years ago. 

 The "supply" is still healthy. It would appear that 

 replanting can be carried out immediately, provided that 

 all dead wood has been removed. 



The disease has been found to originate on jungle 

 stumps in one instance in tea. In another case it was 

 common on Hevea, planted among cocoa, where the 

 intermediate rows of cocoa had been cut out to make 

 room for the Hevea. It may, indeed, be said that a large 

 proportion of the cases of brown root disease on Hevea 

 in Ceylon are on old cocoa land. On new clearings in 

 Ceylon it has not been found possible to trace the disease 

 to jungle stumps. Bancroft, however, states that in 

 Malaya each case of infection has been referable to the 

 presence of a jungle stump. 



But in the majority of its occurrences in Ceylon, other 

 than on Hevea, brown root disease has killed plants in 

 old-established cultivations where no jungle stumps 

 existed. This is notably the case in tea and Grevillea. 

 In such cases only an infection by means of spores appears 

 possible. Here we are met by a difficulty. As a rule 

 Hymenochsete noxia does not produce spores, or, indeed, 

 a fructification. When the fungus has grown up the tap- 

 root and reached the surface of the soil, where it should 

 begin to form its fructification, it usually ceases altogether 

 to grow in that direction. In several cases in Hevea, 

 tea, and cocoa, stumps of diseased plants have been left 

 undisturbed in the hope that they would develop the 

 fructification, but all have ultimately succumbed to white 

 ants without doing so, though some have persisted for 

 four years. Sometimes the fungus does ascend farther 

 up the stem, forming a brown velvety coat, but as a rule 

 this is present only in small patches. If the root is dug 

 up, planted in a pot, and kept under favourable conditions 

 for the development of the fungus no greater success 

 results. Experience in Malaya would appear to agree 

 with this. Bancroft states that the fungus does not 

 apparently fruit in abundance in that country; he had 

 only been able to find a single fruit on camphor, and 

 that a badly developed specimen. 



Recent investigations into brown root disease on 



