CHAPTER VIII 



THE PESTS AND DISEASES OF HRVEA 



Plantation Conditions. 



PROBABLY no species of plant is exempt from the 

 attacks of some kind of animal or vegetable enemy or 

 parasite. Under natural conditions, however, it is rare 

 to find any disease developing the proportions of an 

 epidemic and killing off large numbers of plants in a 

 particular area. In the case of tropical trees like Hevea, 

 one very good reason for the absence of epidemics 

 under the ordinary conditions of forest growth is readily 

 discernible. Unlike the uniform woods characteristic of 

 temperate climates, a tropical forest almost invariably 

 consists of a varied mixture of different species of trees. 

 This mixed character of tropical vegetation extends so 

 far that it has been estimated that as many as three 

 hundred different species of trees are often to be found 

 on a single acre of ground, whilst two individuals of the 

 same species practically never stand side by side. 



The conditions obtaining in a plantation are pre- 

 cisely the reverse of those natural to a tropical forest. 



