( 3 ) 
During the last decade, however, many investigators 
have been engaged on disease problems wherever 
Hevea brasiliensis has been established on a large 
scale, so that our knowledge of the more important 
aspects of rubber diseases is now fairly extensive. 
It. is important to mention here that information 
obtained in respect of diseases in one country does 
not necessarily apply, without modification, to other 
countries. Growth conditions in different countries 
may vary enormously, and this may influence the 
conclusions to be drawn from any research to such 
an extent that any recommendations may apply only 
in the country concerned. Any conclusions stated 
in this article must, therefore, be regarded as not 
necessarily applicable to countries other than 
Malaya. 
Rubber diseases in Malaya can be classified as : — 
(a) root diseases. 
( b ) stem and branch diseases. 
(c) bark diseases. 
The above divisions are self-explanatory with the 
exception of (c). Bark diseases are so called be- 
cause they occur when the tree is tapped for the 
extraction of latex. The latex flows from the 
cortical tissues when a thin paring of cortex is 
excised by the tapping knife. The tapping is done 
at regular intervals, usually once per day or once 
every two days, and each tapping exposes a thin 
strip of tender tissue and forms a suitable place of 
entry for certain fungi. Bark diseases are, there- 
fore, diseases of the tapped surface. 
Root In dealing with root diseases, reference 
Diseases. must be made to the method of opening 
up the land previous to planting. Most 
Malayan plantations are started on virgin jungle 
gp, ' 4 % 
