116 CACAO 



natural checks at present known to exist, disease would 

 soon destroy the very best cultivated fields, in spite of 

 any control measures that have been devised. Sprays 

 and other applications are good in their way, and must be 

 recommended in certain cases, but where the danger of 

 reinfection from surroundings is so great as it is in most 

 cacao countries, they can only have a passing effect ; 

 but a certain knowledge of Nature's control methods must 

 readily indicate procedure which will be of permanent 

 service and much less costly than the methods advised 

 by those plant pathologists who confine themselves to 

 the application of remedies alone. 



Nos. 14 and 15. " Leaf Miner " and " Pod Miner."— 

 The larvse of these insects bore irregular channels just 

 beneath the epidermal layers of leaf and pod. Whether 

 the same insect affects leaf and pod appears as yet un- 

 determined. So far as our observation instructs us, these 

 larvse appear to belong to a small lepidopterous insect, 

 probably one of the Tineidce. They disfigure the pods 

 very much but the leaves are less damaged, and it is not 

 apparent that serious harm is done. They have been 

 observed to be attacked by a small hymenopterous insect 

 which carries off the larvae. As there are openings to the 

 mined channels, it is clear that fungus spores may obtain 

 access, but on the other hand mined pods are seen un- 

 infected, and the chief damage at present appears to be 

 disfiguration. 



No. 16. " Thrip " or " Thrips."— These insects belong 

 to the Thysanoptera, which contain several families and a 

 large number of genera and species. The most important 

 at present is one determined as Physopus rubrocinctus, 

 which has been found doing considerable damage to cacao 

 in Grenada, Guadeloupe, St. Lucia, and Dominica. A 

 similar insect is also reported from Ceylon. 



Physopus rubrocinctus is an insect -^^ to -^ in. in length. 

 " The adult insect is dark brown or black, with delicate 

 wings fringed with fine hairs. The young, which have no 

 wings, are pale or yellowish green, generally with a bright 



