DISEASES 



259 



more strict attention and discriminating investigation are now 

 given to plant diseases than ever in the past, and thus hitherto 

 unnoticed diseases are tabulated. But Professor Erikson says 

 while that is so, what are undoubtedly fresh fungoid diseases 

 have recently appeared in various countries. This is accounted 

 for by the fact that cultivation of great masses of any particular 

 plant generates new characteristics in individual plants and 



FIG. 70. Illustration showing Lace-like I FIG. 71. Illustration showing Fructi- 

 Films of Fomes on Roots of Fallen | fication (Spore-bearing Organ) of 

 Tree. j Fomes. 



(Both Photos by Mr Richards, Mycologist, Caledonia Estate, Straits Settlements.) 



some of the new forms are from their nature more liable to 

 disease and in their turn may affect a whole plantation. 



Although Professor Erikson's investigations have been 

 confined to countries in temperate regions, and do not include 

 the Tropics, yet the dangers are greater there. 



In the case of rubber cultivation the numbers of the trees of 

 one species, the Rev ea Brasiliensis, which have been planted are 

 so vast as to render them specially liable to attack. The dangers 

 likely to arise from an epidemic have been often pointed out by 

 Mr Herbert Wright and others. So far rubber plantations have 

 escaped epidemics like the coffee blight, which swept the coffee 



