1922.] 175 



Notes on the Proclaimed Diseases and Pests, 



BUD-ROT DISEASE OF COCONUT. 



Bud-rot of coconuts is a much-discussed and apparently common 

 disease about which very little is definitely known. The confusion that 

 exists is without doubt dv:e, in great part, to the fact that the heart of 

 the coconut palm, consisting of a large amount of very tender tissue, is 

 naturally the first part to undergo secondary decay when the tree is 

 dying from any cause. Owing to its enclosed situation this decay is 

 usually of a putrid bacterial type, which cannot be distinguished from 

 true bud-rot disease due to direct infection. Such disease undoubtedly 

 exists, but in the present state of our knowledge is only recognisable 

 by its infectious nature. Losses due to red -ring disease, and probably 

 also undescribed root diseases, are often attributed to bud-rot owing to 

 the occurrence of secondary putrefaction of the bud as a conspicuous 

 symptom. 



Infectious bud-rot itself is of uncertain origin. In part it has been 

 shown to be caused by a fungus of the genus Phytophthora, but the 

 more common type in the West Indies appears to be due to one or 

 more species of bacteria. The safest plan is to treat all cases of failure, 

 not definitely assignable to other causes, as due to infectious bud-rot. 



There are two fairly distinct types recognizable. In one the infection 

 is central, and the heart leaf or leaves dry up while all or many of the outer 

 leaves are still healthy in appearance. In the other the infection begins 

 among the outer leaf-bases and works inwards towards the centre. The 

 former type cannot be treated, as the bud is destroyed before the attack 

 is noticed ; the latter type sometimes responds to treatment. Firing 

 the top is not recommended, as the scorched tissues attract beetles 

 which often kill the tree. A safer method is to tie a quantity of copper 

 sulphate in a piece of sacking and fasten it so that its solution in rain 

 water runs down among the leaf-bases. This is more popular than 

 spraying with Bordeaux mixture, which is probably the best remedy if 

 it can be carried out and repeated from time to time. 



RED RING DISEASE OF COCONUT. 



The disease for which the above name is now used was first described 

 from Trinidad in 1905. It was usually known as root 'disease until 1918 

 when it was found to be due to a nematode worm related to the hook- 

 worm which affects man. The adult worm measures only ./j inch in 

 length but is present in the affected tree in countless numbers. The 

 infestation has its principal seat in the stem but extends to the bases of 

 the leaves and at a somewhat late stage to the spongy tissues of the roots. 



The disease is easily confused with bud-rot as in its latest stages the 

 heart generally undergoes secondary putrefaction causing the central 

 shoot to fall over. 



