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CACAO 189 



reduced. The diseased fruits should be burned. When 

 severe it would be well to spray with Bordeaux. The 

 first spraying should be given when the pods just set, 

 and repeated as often as circumstances demand. 



Seedling Disease. This disease has been reported by 

 Massee, who found it on seeds and on seedlings grown 

 from seeds from Jamaica. It is due to a fungus Ramu- 

 laria necator, Massee, which appears on the cotyledons 

 soon after germination, covering them with a dense 

 white mould, and finally killing the young plants. Since 

 it has not been studied in the tropics its relative 

 importance is not known. It is also reported from 

 Dominica. 



Root Diseases. These diseases are very abundant, 

 and have been reported from many places. They 

 usually spread underground from tree to tree, and the 

 roots become infested with mycelium which invades 

 their tissues. The diseased condition of the roots 

 becomes manifest by the appearance of the upper parts 

 of the tree. However, the symptoms vary with 

 different organisms and under different conditions. 

 Usually the leaves are small and yellowish. They 

 wilt, the branches wither, and the trees finally die. 

 In some cases death is very rapid, and in other cases 

 very slow. The fungus may be present on the roots 

 a long time before the tree shows any indication of 

 disease. Organisms other than fungi may also cause 

 root diseases (see page 67). Comparatively little 

 attention has been given to the root diseases caused 

 by fungi. However, the investigations thus far have 

 proved them to be due to Polyporus sp., Hymeno- 

 chaeteae sp. (Ceylon), Sporotrichum sp. (Java), 

 Macrophoma vistita, Prill, and Del. (in Central 

 America), Pomes semitostus, Berk. (Ceylon), and there 

 are doubtless many others. 



The difficulties in treating this class of diseases 

 are many. The organisms which cause them also 

 attack other species and varieties of trees, both culti- 

 vated and uncultivated. Very frequently an old log 



