280 SCIENCE IN AFRICA 



partly true, since much of the laborious research work has to be 

 repeated for each kind of environment and for each association of 

 tsetse species. In West Africa, therefore, it appears that further 

 development of research organizations is called for, while in East 

 Africa the field problems have reached a stage of research when 

 they can profitably be taken into the laboratory for controlled 

 experiment, such as has already been described. 



INSECT PESTS OF CULTIVATION 



A brief review of so wide a subject as this must be limited to 

 major pests and to the branches of research which are obviously 

 important. Even within these limits it must aim rather at indicat- 

 ing the kind of work that is being done than at the evaluation of 

 achievements. The following paragraphs are therefore illustrative, 

 rather than critical, and the facts mentioned are intended more as 

 examples of important lines of research than as an account of all 

 the valuable work that has been done. It is impossible to do more 

 than mention, for instance, the necessary routine work of ento- 

 mologists who succeed, for the most part, in keeping within reason- 

 able bounds insect pests that cause a fairly regular loss to the major 

 crops. The time which agricultural entomologists have to spend 

 in such work limits their research to experiments centred on 

 routine duties, and to the discovery of ways of controlling sudden 

 and destructive infestations. 



It is obvious that in Africa large distances, poor communica- 

 tions and often sparse population make field work far more diffi- 

 cult and irregular than it is in Europe. But what limits research 

 and the application of experimental results more than anything 

 else is the ignorance of the native population. Control measures 

 requiring methodical care and precision, which are confidently 

 recommended to growers in the United States, for example, can- 

 not be entrusted to uneducated natives. The fact that even in 

 such a highly developed country as Egypt all fumigation has to be 

 carried out by special Government officials illustrates the diffi- 

 culty of popularizing such control measures. Some idea of the 

 general nature of such difficulties and of the means adopted to 

 overcome them may be obtained from the reports of the Conferences 



