DISEASES AND ENEMIES 251 



into the twigs and branches by means of existing small 

 or large wounds, prevention is best attained by keeping 

 the branch and foliage system in strong and healthy 

 condition, by avoiding enemies like thrips which de- 

 foliate the tree, by keeping the wind off, and by seeing 

 that the trees are not suddenly exposed to the full 

 sunlight by removing the shade too abruptly. All 

 dead wood should be quickly pruned off. After pruning 

 the cut surfaces must be carefully treated with black 

 tar, and accordingly pruning should only be done in 

 the dry season. When a branch shows symptoms of 

 the disease, the tree can often be saved by cutting the 

 branch off; and even when the Diplodia has already 

 penetrated into the stem, it is often successful to cut 

 the tree down to within a foot or so from the ground. 



Djamoer oepas (Corticiumjavanicum). This para- 

 site is here and there the cause of the death of branches 

 in the cocoa fields in Java and Ceylon. 



The fungus starts its growth on the outside of a 

 branch in the form of a tiny cobweb-like overgrowth, 

 which gradually forms whitish or reddish crusts which 

 especially develop on the side turned away from the 

 sunlight (Fig. 82). In this stadium the fungus can 

 penetrate into the wood, and then begins to be harmful 

 to the branch. On these crusts the Corticium fructifica- 

 tion is formed. Gradually the branch dies, and on the 

 dead branch the fungus often forms another fructifica- 

 tion, which was formerly regarded as belonging to 

 another fungus and was called Necator decretus. This 

 fructification has a stone-red, waxy appearance, and is 

 formed principally in clefts of the dead branch, especially 

 on the upper side. 



The " djamoer oepas " fungus attacks a great number 

 of plants, but the damage it causes varies widely. It 

 is often found on tea, for instance, but seems unable 

 to penetrate into the wood ; it only grows superficially 

 on the bark, and the harm done to the tea plant is 

 unimportant. 



In Java it is not very common on the cocoa tree, 



