COCOA 51 



those described above, often render the tree more sus- 

 ceptible to the attacks of insect pests ; but, although it 

 has been stated that cocoa trees in the Gold Coast are 

 seriously affected in this way, such is not often the case. 

 Beetles of the Longicorn group are found damaging the 

 tree to some extent wherever it has been planted. Two 

 species are recorded from the West Indies : Steirastoma 

 histrionica, White, from Trinidad, and S. depressa, Linn., 

 from Grenada. On the trees in the Gold Coast Armato- 

 sterna buquetiana, White, and a Glenea sp. have been found 

 doing similar damage. These insects deposit their eggs 

 in crevices of the bark or on wounds, and the grubs which 

 emerge bore into the trunk, living and growing in size 

 in the interior of the wood until mature, when they 

 change into pupse, and finally into beetles. The presence 

 of these grubs is easily detected by the quantity of fine 

 particles of wood or " frass " which are thrown out of 

 the entrance hole ; and, if a flexible wire be inserted until 

 it reaches and impales the grub, it will often prevent 

 the damage becoming serious. The nests of large red ants 

 ((Ecophylla sp.), which feed upon the saccharine juices 

 which exude from the pods, may often be observed on 

 cocoa trees, but as the ants viciously bite any living thing 

 which may venture upon the tree, they are probably a 

 safeguard against the depredations of rats and squirrels 

 that eat out the contents of the ripe fruit while still on 

 the tree. 



In 1909 the writer drew attention to a black hemip- 

 terous insect causing destruction to plantations in the 

 Ashanti-Akim region, where careless cultivation prevailed 

 (cf. Bull Entom. Research, vol. i. pt. viii. 1910). This 

 insect, known as the " Black cocoa-bark bug" or " San- 

 konuabo," was named Sahlbergella theobroma, Distant, 

 and subsists in all its stages upon the sap of cocoa branches 

 obtained through punctures made by its proboscis.* 

 The attacked trees are atrophied or killed outright 

 (Fig. 16). Spraying with petroleum -soap emulsion has 

 proved an effective remedy, but native planters do not 

 readily adopt it. Recently the insect has been found 

 sapping the silk cotton tree, and planters are warned 

 against having this tree in their plantations. 



* S. singularis, a nearly allied insect, is common in certain localities 

 and does similar damage. 



