48 THE RUBBER INDUSTRY 



interests connected with the Booth Steamship Company 

 and the Port of Para. It is possible that some sections 

 of the Amazon Valley may be free from this pest ; but 

 the area tested included both forest and plantation trees, 

 dry and wet lands, and all classes of soil, and was con- 

 tinued under varying atmospheric conditions. In dry 

 weather the wounds healed and the growth of new bark 

 was rapid ; but with the resumption of tapping the dis- 

 ease reappeared immediately a wet period occurred, and 

 this necessitated the suspension of the work. 



Another disease of the bark common to rubber-trees 

 in the Amazon Valley is a decay of the latex cells on 

 untapped portions of the stem, The result is a copious 

 exudation of the gum through the outer skin ; there 

 it collects moisture, and leads gradually to the putrefac- 

 tion of the surface bark, thence affecting the cortex, and 

 finally extending to the wood and rotting away the 

 trunk until the tree is killed. The danger from this 

 cause would be minimized if the tree trunks were main- 

 tained in a clean condition, but here, again, effective 

 supervision to this end is not available under existing 

 circumstances. 



Of the insect pests, the borer is the most destructive 

 to mature forest trees, and no section of the Amazon 

 Valley is free from it. Wherever the wood of the stem 

 has been laid bare it is liable to attack, and this con- 

 dition occurs to a very large proportion of the rubber- 

 trees, on account of the careless use of the machadinho 

 by the collectors. The borer cuts its way to the centre 

 of the trunk, and in a comparatively short time hollows 

 out the heart of the tree, leaving it without power to 

 resist the force of a strong gust of wind, and with the 



