52 



carbolineum or some other disinfectant. After a few weeks ta|)ping 

 can be started again ; in some cases it is not necessary to stop 

 tapping." As preventive measures they point out timt free access of 

 air and light should be given to the trees in the plantation by 

 thinning out, that there should be a thorough system of drainage 

 and the use of water in tapping should be avoided. 



Dastur, who did the work on the disease in Burma, suggests 

 cessation of tapping at the first appearance of the disease and the 

 collection and destruction of all diseased fruits. 



In South India an effective method is said to be the cessation of 

 tapping on affected trees and a mixture of tar and tallow smeared 

 over the diseased area of bark. 



Patch says " When the tapped surface shows signs of decay it 

 should be brushed over twice a week for three weeks with a solution 

 (20 per cent.) of brunolinum (brunolinura one gallon, water four 

 gallons, soft soap one lb.) The canker patches must be cut out and 

 the diseased tissue burnt." 



I have not as yet been able to draw any very definite conclusions 

 from the experimental treatment adopted on the various estates 

 affected but hereunder I make suggestions which may be acted upon 

 at once should the disease be found on j'our estate. 



. Prior to making suggestions it is necessary to understand the 

 conditions which favour the growth and spread of the fungus. 

 All species of PhytopMhora, the potato disease of Ireland caused by 

 Pfiytophthora infestans is one example, need excessive humidity for 

 their development. Any particular cause which has the effect of 

 preventing the drying up of moisture on the tapping or tapped 

 surface should be eliminated if such elimination is possible. One 

 cannot prevent rainfall but it is possible by one or more of several 

 means to increase the rate at which the moisture on the bark will 

 evaporate. 



It does not follow that because a method of treatment is 

 successful in one country it is necessarily a success in another 

 country or another part of the same country because conditions, 

 particularly atmospheric conditions, vary so considerably. 



In Burma, for example, there is a distinct wet season and 

 it is during this season that the disease is prevalent. In this 

 country again it seems to me that the fungus, for some unexplained 

 reason, penetrates more deeply into the tissues of the plant, to a 

 considerable deptli in the wood, than, from the information obtain- 

 able, in other parts of the East, where Hevea is planted. It would 

 appear then that what may be an unavoidably drastic measure in one 

 place could be extremely unnecessary in others even in the same 

 country. 



