ENTOMOLOGY 285 



parasite, Microbracon kirkpatricki, by means of an alternative host. 



The cotton worm [Prodenia litura F. ) , described by Bishara ( 1 934) , 

 is a major pest in Egypt, Tanganyika, French Equatorial Africa, 

 and Italian Somaliland. It feeds on the leaves and by weakening 

 the plants renders them more susceptible to bollworms. 



It appears from the reports received by the Empire Cotton 

 Growing Corporation from Experiment Stations (i934b-38) that 

 cotton stainers {Dysdercus spp.), bugs which transmit Nematospora 

 gossypii and N. corjli, seem to be best controlled through their alter- 

 native food-plants, the wide range of which allows a long breeding 

 season. In Rhodesia they migrate from early-flowering Hibiscus 

 and from Thespesia to cotton in February, and return in May to 

 late-flowering Hibiscus. In an area free from Thespesia the stainers 

 appeared on cotton too late to cause much damage. In the Sudan, 

 spraying baobabs [Adansonia digitata) with kerosene ten days after 

 burning the cotton gave fairly good control. Some account of 

 stainers in South Africa is given by Ullyett (1930). 



The cotton whitefly [Bemisia gossypiperda Misra and Lamba) is a 

 serious pest in the Sudan, Tanganyika, Southern Rhodesia, and 

 the Belgian Congo. It has been thought that it transmits the disease 

 known as leaf-curl of cotton (Kirkpatrick 1930, 193 1), but in 

 Tanganyika there are indications that the latter is due to a capsid. 

 In the Sudan whitefly is sometimes checked by natural enemies 

 after the winter. Since direct control is impracticable, experi- 

 ments have been made to produce resistant strains of cotton, and 

 two such strains of Sakel cotton have been bred successfully in 

 the Sudan, and one Ishan strain has been grown for the last nine 

 years in Nigeria, where the local vector of leaf-curl was discovered 

 in 1929. 



Capsid bugs of the genus Helopeltis are widely distributed over 

 the western part of Africa and in Uganda. Attack by Helopeltis 

 on cotton leaf and stems produces respectively spots and lesions 

 which are difficult or, when old, impossible to distinguish from 

 those caused by Bacterium malvacearum, which latter are known 

 respectively as 'angular leaf-spot' and 'black-arm' diseaes (Han- 

 cock 1935 and Steyaert and Vrydagh 1933). 



Jassid bugs known as leaf-hoppers {Empoasca fascialis and other 

 spp.) have been serious pests in many parts of Africa; they may be 



