654 MISCELLANEOUS SUBJECTS 



of leaf disease is not to be of great duration, and that 

 succeeding years may see coffee estates comparatively free 

 from disease. Again, the disease being endemic, cannot 

 be expected to work the havoc that it wrought in Ceylon. 

 Experiments with sprays and powders have been con- 

 ducted. Sulphur and lime used as a powder, and various 

 solutions of salt and lime in water used as a spray, have 

 given disappointing results. The best results have been 

 got from the use of Bordeaux and Burgundy mixtures. 

 These are suitable for use at any time, and particularly 

 before the onset of wet weather, as a necessary preventive 

 measure. 



The behaviour of Hemileia is essentially that recorded 

 from other parts. Infection takes place readily. The 

 atmosphere in most parts is humid overnight, heavy dews 

 are usual, and the temperature is seldom low enough to 

 hinder germination. Disease spots on the leaf may 

 number over one hundred, or be so numerous as to conceal 

 entirely, with masses of uredospores, the whole under- 

 surface of the leaf. I have never found Hemileia on any 

 part but the leaf. 



The teleutospores are very rarely met with, and never 

 on leaves which are still adherent to the trees. 



A search has been made, but not as systematically as 

 could be wished, for a possible JEcidium condition. Un- 

 fortunately, the element of chance entering into this 

 research is great. When found the intermediate host 

 may not be easily extirpated, and again, its destruction 

 might not affect the prevalence of the uredo-stage of the 

 fungus. 



The following genera of the Rubiaceae occur in the 

 Victoria Nyanza Region: Mitragyne, Oldenlandia, 

 Muss&nda, Dutyandra, Gardenia, Belonophora, Can- 

 thium, Vangucria, Craterispermum, and Pavetta, 



At least four of these genera have been found to 

 harbour species of Hemileia in other parts. 



On the whole, one is safe to conclude that the present 

 outlook is favourable to coffee planters in Uganda, not 

 only because of indications that the disease may be less 

 virulent than formerly, but also, and especially, because 

 planters are realizing that measures must be taken against 

 Hemileia. 



