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WEST AFRICAN HEMIPTERA INJURIOUS TO COCOA. 



By GEEALD C. DUDGEON, 



Inspector of Agriculture for British A\^est Africa. 



In the Bulletin o£ Entomological Research, Vol. I. pp. 60-61, I gave an 

 account of ihe ravages of a cocoa bark-sapper (SaJdhergeUa tlieohroma^ Dist.), 

 which wns found destroying cocoa trees upon plantations in some parts of 

 the Gold Coast and Ashanti, where, by reason of its wide distribution in 

 1909, it promised to affect the industry seriously. 



In January 1910 I again visited Bompata (Ashanti), one of the localities 

 where the pest had been prevalent during the previous spring, and found 

 that, although the black bark-sapper {S. theohroma) did not seem quite so 

 plentiful, a very nearly allied species [S. singularis, Hagl.) was present upon 

 almost every tree in badly infested plantations. This species is distinguished 

 from the last by the lioht brown colour and the brown mottlino- of the 

 hemielytra as well as by the slightly different form of the antenna. 



The habits of the two species are similar and their responsibility for the 

 destruction of the trees has been recognised even by the native cocoa- 

 planters at Bompata. The officers of the Agricultural Department have 

 frequently visited this locality and have demonstrated this fact as well 

 as the correct application of the remedial measures which have been 

 recommended. 



Experimenting with kerosene emulsion, I found that if a large quantity 

 of soap were used the syringes soon became clogged, and the following 

 preparation was tried and found the most suitable : — One pound of soap was 

 dissolved by boiling in two gallons of water to which, while hot, four gallons 

 of kerosene were added and thoroughly mixed by syringing. One part of 

 this stock solution was mixed with nine parts of water for use when spraying. 

 This last, sprayed upon living immature insects upon the trees caused them 

 to run to shelter into bark crevices, in which after three or four minutes 

 they were found to be killed. As the insects are said to congregate upon 

 the trunks of the trees in the early morning, this time seems indicated as 

 that most suitable for spraying. 



The pest has extended to the west of Kumassi, where cocoa has only been 

 planted to a small extent at present, but where insufficient care seems 

 to have been given with regard to weeding and keeping the plantations 

 clean. An examination of the stems attacked by the sappers showed that 

 there was frequently an exudation of a gelatinous substance, and indications 

 of the presence of fungoid disease in the cambium were found. 



BULL. ENT. RES. VOL. I. PART 3, OCTOBER I 9 10. Q 



