DISEASES AND PESTS >i 



and is often propagated from seeds dropped by birds^ 

 and lodging in crevices of the bark or in joints where 

 moisture has collected. The injurious character of this 

 parasite is recognized locally, but no effort is made to 

 eradicate it from the trees affected, or in any way check 

 its spread. In every district the annual loss from this 

 plague amounts to many thousands of trees. 



Canker is of frequent occurrence on both wild and 

 planted trees. It is found generally at the junction of 

 the main lateral branches with the trunk, where a lodg- 

 ment of rain-water has taken place. The effect is to 

 rot both branches and stem until the tree becomes 

 exhausted and dies. No attention is paid to it, and the 

 disease is allowed invariably to run its course, although 

 a very little energy at the outset in the direction of 

 pruning away the affected parts would insure a com- 

 plete recovery. 



The most common form of bark disease is a ftfngoid 

 growth carrying a black powdery substance on the 

 surface. It appears first near the foot of the tree, and 

 gradually spreads up the stem to the main lateral 

 branches. For the most part it is found in low-lying 

 localities, where the soil is a stiff yellow clay. The 

 obvious remedy is adequate drainage and the application 

 of lime ; but the circumstances connected with the wild 

 rubber industry render any action of this nature 

 practically impossible, and where it occurs on planta- 

 tions the cost of labour and the general apathy of the 

 owners prevent any effective attempt being made to 

 grapple with it. 



The existence of cambium rot in the Amazon Valley 

 threatens to exercise a rrfbst unfavourable influence in 



