62 



THE COCO-NUT 



CHAP. 



opinion that the disease is always purely bacterial must 

 suppose that the bacteria either attack the old leaves 

 directly or that the progress of the disease toward the 

 heart of the tree is very slow in such cases, and that 

 recovery in such cases is not rare. 



With regard to treatment, Johnston has made a care- 

 ful test of some of the remedial measures repeatedly 

 suggested in the West Indies. In his experience none 

 of these offers any promise. With regard to chemi- 

 cal treatment, Johnston reports experiments with salt, 

 copper sulphate, and Paris green, without good results 

 in any case. His report on tree No. 286, page 57 

 of his work, is typical. 



March 11 : Nine spikes of nuts and good open flower spike. 



May 28 : Same. 



June 6 : Practically the same. 



June 29 : Appeared unhealthy. 



July 6 : Had dropped 15 immature nuts ; 5 spikes of few 

 nuts ; and above were 5 or 6 spikes of no nuts ; 3 good 

 swords and good middle leaves. Placed 1 kilogram of 

 copper - sulphate crystals at the bases of the leaves. 

 Eains were so frequent that the crystals were soon 

 dissolved. 



July 21 : Showed one open discoloured flower spike. 

 August 6 : Only 2 nuts and many empty spikes on tree ; a 



dead flower spike, opened some time ago, and one just 



opening. 



October 21 : Central leaves bent over dry and dead ; swords 

 dead ; many empty spikes ; all leaves yellow. 



Johnston did not try flaming the trees because 

 satisfied in advance it would be useless. 



It has been contended by some people applying this treat- 

 ment to their trees that there was subsequent recovery from 

 the disease, at least to the extent of flower spikes opening out 

 and setting nuts. It should be noted, however, that the tree, 

 while retaining the disease, may send forth new flower-spikes 

 and nuts for a period of at least a year after infection has 

 taken place without any treatment having been applied. 

 The writer possesses records of individual trees which show 

 this. In many trees flamed the disease progressed subsequently, 

 so that it presented to the writer no evidence of the value of 



