204 DISEASES OF TROPICAL PLANTS CH. 



Travancore 1 which attacks the coco-nut palm (Cocos 

 nucifera), the talipot (Corypha umbraculifera), and the 

 sago palm (Caryota urens). This disease works very 

 slowly, causing the leaves to droop and lose colour. 

 The tips of the leaflets turn yellow and become dry, 

 and finally the entire leaf does the same. They are 

 then easily torn off'. As the disease progresses the 

 leaves become smaller and fewer. The kernels are 

 frequently shrivelled and deficient in oil. Finally, the 

 cabbage rots and the tree is dead. This disease was at 

 one time supposed to be due to Thielaviopsis ethacetica, 

 Went, which is the cause of the so-called " pine- apple " 

 disease of the sugar-cane ; but Butler has demonstrated 

 that although this fungus is frequently found upon 

 many species of palms it is not the cause of the disease. 



Examination of the roots shows that they have been 

 invaded by the mycelium of a fungus which kills them 

 and causes the roots to turn brown, and then to become 

 black and shrunken. Mr. Butler was unable to find 

 trace of the fungus in the trunk. The fungus on the 

 root proved to be a Botryodiplodia sp., but Mr. Butler 

 could not be positive that it was the cause of the 

 disease. The disease is no doubt infectious, and if the 

 fungus is the cause, it probably spreads through the soil. 



It is possible to control it to some extent by de- 

 stroying the debris, adding lime to the soil and allowing 

 it to rest for a time where possible. Select healthy 

 trees which are as near immune as possible, and fertilize 

 freely. 



Mr. F. A. Stockdale has described a similar disease 

 for Trinidad, which also occurs in British Guiana, and 

 possibly Jamaica, but in this case he found the spores on 

 the petiole. It is very doubtful if it is the same as the 

 disease described by Butler. However, the disease is due 

 to a species of Botryodiplodia. It works very slowly, 

 causing the leaves to wilt, turn yellow at the tips, become 

 dry, and hang down for some time before falling. Some- 

 times these hanging leaves entirely enclose the trunk. 



1 See Agri. Research Institute (Pusa), Bui. 9, March 1909. 



