PLANT DISEASES 407 
lower Rio Negro. The midges concerned in the production of this disease were 
identified and described by Felt and Bequaert ! in the Amazon Report as Cecido- 
mya manihot. Other diseases affecting mandioca have been investigated by 
Rahm * who has recently found five species of nematodes invading the roots of 
this plant in Brazil. Since our investigations were made in Liberia, McKinney ? 

No. 345. — Potted quinine plant ready for shipment, Eala 
has visited Monrovia and has observed mosaic disease there on cultivated egg 
plants, peppers, Capsicum frutescens, as well as on cassava. 
Cinchona infection. A disease of especial interest to students of tropical 
biology and medicine is one which affects the quinine plant, Cinchona succirubra. 
The Government botanical garden of Eala is situated near Coquilhatville on the 
Congo River. One of its purposes is to develop agriculture in the Congo and also 
to bring about acclimatization of foreign useful plants and cultivate them 
experimentally. Here cultivation of both chaulmoogra and Hydnocarpus plants 
(used for the treatment of leprosy) and of Cinchona plants, is carried on. The 
young plants are potted in baskets and sent from these nurseries to different 
parts of the Belgian Congo for planting and cultivation. 
Among some of the beds of young Cinchona succirubra plants, from one to 
1 Felt and Bequaert: Medical Report of the Rice 7th Exped. to the Amazon (1926), p. 204. 
= Henm<: Loc. ¢7., p-. 107. 
3 McKinney: Jour. Agri. Research (1929), XX XIX, 557. 
