640 RUBBER 



During the rainy season T. gestroi will frequently 

 encase the trunk of a rubber tree with mud, and when 

 this happens it provides the only definite proof that a 

 tree is affected by this pest. Such trees are usually 

 marked in some conspicuous way, e.g., by tying a red 

 piece of cloth round them, and are subsequently treated. 



More remedies have been tried in connection with this 

 insect's attacks upon rubber than in the case of any 

 other pest in the Malay States. It may safely be con- 

 cluded from present experience that the only efficient 

 remedy is to apply the fumes of arsenic and sulphur by 

 means of the " Universal White Ant Exterminator," 

 which has been used extensively in South Africa and 

 Ceylon, although not for T. gestroi, and is extensively 

 used in the Federated Malay States. This machine was 

 imported here in 1908, when several trees in the experi- 

 mental gardens were treated for termite attack. There 

 has been no recurrence of attack on any of these trees 

 since that time, now six years ago. The fumes, which 

 are pumped either into the tree or into the runs, are 

 formed by arsenic and sulphur placed on red-hot charcoal. 

 The charcoal is placed within the cylinder made for the 

 purpose, the fumes being forced through a flexible 

 tubing, fitted with a nozzle, by means of an attached 

 pump, which also keeps the charcoal red hot. The pro- 

 portion of arsenic and sulphur is, I believe, 80 and 

 20 per cent, respectively. This machine is of especial 

 value, and very easy to work in destroying those colonies 

 of termites which form mounds. 



Quite a fair proportion of young trees which are 

 treated in this way for T. gestroi die within a few weeks, 

 although there may be no return of this pest. Such 

 cases I attribute to the presence of fungus previous to 

 termite attack. In quite a number of instances there is 

 evidence for the assumption that the insect not only 

 checks the growth of root fungi, but actually destroys 

 all traces of it, and such trees when treated for termite 

 attack will recover, and continue to give good yields for 

 many years. 



