FIELD STUDIES OF THE DISEASE. 59 



first used in Jamaica and subsequently adopted in Cuba. The method 

 consists in sotting fire to the crown, either by Hghting the (hy pendent 

 leaves or by the addition of coal oil. It is desired to create consider- 

 able heat in and about the base of the crown and not in the central 

 leaves nor among the upper green leaves. The writer made no ex- 

 periments with this method as, after the studies on the arrangement 

 of the crown leaves and experiments with the external treatment 

 of other kinds, it was considered to have no practical value. More- 

 over, an examination of the results of such treatment carried out by 

 several investigators and by planters led to the same conclusion. 



The conclusions reached, after carefully examining different trees 

 treated by various workers and watching the progress of many trees 

 so treated during a period of a year, are as follows : 



From the arrangement of the crown it is impossible for the heat to 

 penetrate into the inner tissues in sufficient degree to dry out the 

 diseased portion without seriously affecting the growing part of the 

 crown. Any flaming whatever will destroy the lower leaves and all 

 the nuts, so that even if the tree is not killed, at least a year's crop is 

 destroyed. The scorching of the leaves and the charring of the trunk 

 so kills the superficial tissues as to permit the rain to soak in and a 

 subsequent rot to take place. It has been contended by some people 

 applying this treatment to their trees that there was subsequent 

 recovery from the disease, at least to the extent of flower spikes open- 

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

 while retaming 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 appHed. 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 this treatment. As a diseased tree is cer- 

 tain to die if not treated, there can be no error in flaming it; but to 

 try this method with healthy trees in the expectation of warding ofl' 

 infection is not advisable, because (1) there is no evidence that the 

 treatment would succeed, and (2) there is the certamty that the tree 

 would be seriously injured in a way that would make it more sus- 

 ceptible to infection. 



PREVENTIVES. 



In order to prevent the spread of the disease, it is necessary to de- 

 stroy its source, or its means of transmission, or the conditions favor- 

 able to its development. The absolute destruction of diseased trees, 

 a careful watch for the newly infected cases, and their immediate 

 removal has done much to prevent greater loss in various regions. 

 In Jamaica it is chiefly owing to this care that the bud-rot is not 

 widespread. In some districts in Cuba care has enabled the planters 



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