CHAPIER X. 



Diseases, &c. — Insect Pests, Fungi, Vegetable Parasites, 

 Epiphytes, and other enemies. 



♦ *-%*/ _^^ 



ORTUNATELY for the cultivator the serious 



x^ViM^ // diseases whicli at present attack the Cacao tree- 



■^^"■iji^' ,' in the West Indies, are few, except the plant i< 



f w'i^t placed in a totally unsuitable position. Perhaps 



I'^^.jM the most common disease affecting the tree, is one 



"^if^iJ^^S ^hifh is known under the name of Canker. This 



cause the stem and branches to dry in certain 



spots and along certain lines and generally results in the death 



of the tree. 



The cause of this disease is not yet fully clear, but a fungus 

 of the parasitic type has been found on Cacao pods, the allies of 

 which are known to cause canker of the bark on other trees. 

 This has been named Nectria baini>, Masaee, and will be 

 discussed later. Generally speaking, however, when trees are 

 planted in well drained ground, little or no disease is found ; but 

 where a poor surface soil badly drained exists, canker will 

 appear (Canker oj t/te bark has also been found to be due to a, 

 Nectria — December, 1899.) 



There is another disease found in Trinidad, Surinam, 

 Grenada and other places, which attacks the pods in damp 

 weather and causes thern to rot and turn black, hence sometimes 

 called •' black rot" or " black Cacao." This is due to a parasitic 

 fundus recently studied and forwarded to Kew by the Author, 

 where it was determined as J'hytophthora omnivora, a fungus 

 akin to that (I'hytophthora infestans) which destroys the 

 Potato {Sulanum tuberosum.) 



The following extract from De Verteuil's Trinidad, liS-t, 

 page 431, reads : — 



" TJie prosperity of the Colony had now rf.aclied its euhninat- 

 ing point, Cacao selliny at a very high price. But In the year 

 1727. according to Gandla, not a disease of llie trees exactly, but 

 a bliyht attacking the pods under certain atmospheric injui^nces, 

 deatr yed the crops. 



