Diseases of the Cacao Tree.
Take, for example, the case of the diseases of plants. Everyone who takes an interest in the garden knows how destructive the insect pests and vegetable parasites can be. In the tropics their power for destruction is very great, and they are a constant menace to economic products like cacao. The importance of understanding their habits, and of studying methods of keeping them in check, is readily appreciated; the planter may be ruined by lacking this knowledge.
The cacao tree has been improved and "domesticated" to satisfy human requirements, a process which has rendered it weaker to resist attacks from pests and parasites. It is usual to classify man amongst the pests, as either from ignorance or by careless handling he can do the tree much harm. Other animal pests are the wanton thieves: monkeys, squirrels and rats, who destroy more fruit than they consume. The insect pests include varieties of beetles, thrips, aphides, scale insects and ants, whilst fungi are the cause of the "Canker" in the stem and branches, the "Witch-broom" disease in twigs and leaves, and the "Black Rot" of pods.
The subject is too immense to be summarised in a few lines, and I recommend readers who wish to know more of this or other division of the science of cacao cultivation, to consult one or more of the four classics in English on this subject:
- Cocoa, by Herbert Wright (Ceylon), 1907.
- Cacao, by J. Hinchley Hart (Trinidad), 1911.
- Cocoa, by W.H. Johnson (Nigeria), 1912.
- Cocoa, by C.J.J. van Hall (Java), 1914.
[1] Bulletin, Botanic Dept., Jamaica, February, 1900.
[2] Bulletin Dept. of Agriculture, Trinidad, 1916.
[3] "How José formed his Cocoa Estate."