COCO-NUT AND OTHER PALMS 203 



originate on the outer surface, and gradually work their 

 way through to the heart. On the surface they become 

 dry and frequently covered with mycelium. Finally, 

 the central shoot turns white, the cabbage becomes 

 putrid, and the crown drops off. The spores are formed 

 on the young blades. This disease threatens the ex- 

 tinction of the Palmyra, coco-nut, and betel-nut palms 

 of many parts of Madras. All diseased trees should be 

 cut and burned as soon as the disease is detected, in 

 order that its spread may be prevented. 



A similar disease has been reported from Ceylon, 

 India, and East Africa, but we cannot say whether it 

 is or is not the same. 



Smut. This disease is due to the fungus Graphiola 

 phoenicis, Poit, and occurs on the leaves of Phoenix 

 dactylifera, Chamaerops humilis, and probably on other 

 palms, but is said to be of little or no consequence, 

 except in conservatories. It causes small dark-coloured 

 spots which project on both surfaces of the leaves. 



Koleroga. This is a disease of the betel nut palm 

 (Areca catechu) which occurs in parts of India, It is 

 due to Phytophthora omnivora, var. Arecae, Coleman, 

 which causes the young nuts and flowers to fall without 

 setting fruit, and the stalks to blacken. It spreads along 

 the flowering shoot, causing the nuts to fall, passes into 

 the leaf-sheath and finally into the centre of the bud, 

 which it destroys. The disease first causes areas on 

 the nut to appear a darker green and water soaked. 

 A little later it becomes covered with a whitish mass of 

 fungus which can be easily scraped off. This stage is 

 soon followed by falling of the nut. The disease is 

 most severe in wet seasons. The spores are carried from 

 one wet season to the next in the old diseased parts or 

 possibly in the soil. It can be controlled by removing 

 and burning the old infected parts and by spraying 

 with Bordeaux mixture. The boiled resin and soda 

 mixture should be added to the Bordeaux to improve 

 its adhesive qualities. 



Mr. E. J. Butler also reports a disease from the 



